1621501045 has 4 divisors (see below), whose sum is σ = 1945801260. Its totient is φ = 1297200832.

The previous prime is 1621501043. The next prime is 1621501067. The reversal of 1621501045 is 5401051261.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5401051261 = 109 ⋅49550929.

It can be written as a sum of positive squares in 2 ways, for example, as 559653649 + 1061847396 = 23657^2 + 32586^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621501045 - 2¹ = 1621501043 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621501043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162150100 + ... + 162150109.

It is an arithmetic number, because the mean of its divisors is an integer number (486450315).

Almost surely, 2^1621501045 is an apocalyptic number.

It is an amenable number.

1621501045 is a deficient number, since it is larger than the sum of its proper divisors (324300215).

1621501045 is an equidigital number, since it uses as much as digits as its factorization.

1621501045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324300214.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 1621501045 is about 40267.8661590107. The cubic root of 1621501045 is about 1174.8229206511.

The spelling of 1621501045 in words is "one billion, six hundred twenty-one million, five hundred one thousand, forty-five".