21002331 has 12 divisors (see below), whose sum is σ = 32575272. Its totient is φ = 12001248.

The previous prime is 21002329. The next prime is 21002341. The reversal of 21002331 is 13320012.

It is a happy number.

It is not a de Polignac number, because 21002331 - 2¹ = 21002329 is a prime.

It is a super-2 number, since 2×21002331² = 882195814867122, which contains 22 as substring.

21002331 is a modest number, since divided by 2331 gives 21 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21002341) 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 11 ways as a sum of consecutive naturals, for example, 71290 + ... + 71583.

It is an arithmetic number, because the mean of its divisors is an integer number (2714606).

Almost surely, 2^21002331 is an apocalyptic number.

21002331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21002331 is a deficient number, since it is larger than the sum of its proper divisors (11572941).

21002331 is a wasteful number, since it uses less digits than its factorization.

21002331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142890 (or 142883 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21002331 is about 4582.8300208496. The cubic root of 21002331 is about 275.9026252799.

Adding to 21002331 its reverse (13320012), we get a palindrome (34322343).

The spelling of 21002331 in words is "twenty-one million, two thousand, three hundred thirty-one".