64531621 has 16 divisors (see below), whose sum is σ = 81100800. Its totient is φ = 49880880.

The previous prime is 64531591. The next prime is 64531633. The reversal of 64531621 is 12613546.

It is not a de Polignac number, because 64531621 - 2⁹ = 64531109 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64531621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64531651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6480 + ... + 13078.

It is an arithmetic number, because the mean of its divisors is an integer number (5068800).

Almost surely, 2^64531621 is an apocalyptic number.

It is an amenable number.

64531621 is a deficient number, since it is larger than the sum of its proper divisors (16569179).

64531621 is a wasteful number, since it uses less digits than its factorization.

64531621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6744.

The product of its digits is 4320, while the sum is 28.

The square root of 64531621 is about 8033.1575983545. The cubic root of 64531621 is about 401.1044911910.

The spelling of 64531621 in words is "sixty-four million, five hundred thirty-one thousand, six hundred twenty-one".