31220001 has 6 divisors (see below), whose sum is σ = 45095570. Its totient is φ = 20813328.

The previous prime is 31219999. The next prime is 31220003. The reversal of 31220001 is 10002213.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31219999) and next prime (31220003).

It can be written as a sum of positive squares in only one way, i.e., 24059025 + 7160976 = 4905^2 + 2676^2 .

It is not a de Polignac number, because 31220001 - 2¹ = 31219999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 3468889 = 31220001 / (3 + 1 + 2 + 2 + 0 + 0 + 0 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31220003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1734436 + ... + 1734453.

Almost surely, 2^31220001 is an apocalyptic number.

It is an amenable number.

31220001 is a deficient number, since it is larger than the sum of its proper divisors (13875569).

31220001 is a wasteful number, since it uses less digits than its factorization.

31220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3468895 (or 3468892 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 31220001 is about 5587.4861073653. The cubic root of 31220001 is about 314.8794398805.

Adding to 31220001 its reverse (10002213), we get a palindrome (41222214).

The spelling of 31220001 in words is "thirty-one million, two hundred twenty thousand, one".