64521556 has 24 divisors (see below), whose sum is σ = 124205760. Its totient is φ = 29325560.

The previous prime is 64521551. The next prime is 64521559. The reversal of 64521556 is 65512546.

It is a super-2 number, since 2×64521556² = 8326062377322272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64521551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 736 + ... + 11383.

It is an arithmetic number, because the mean of its divisors is an integer number (5175240).

Almost surely, 2^64521556 is an apocalyptic number.

It is an amenable number.

64521556 is a deficient number, since it is larger than the sum of its proper divisors (59684204).

64521556 is a wasteful number, since it uses less digits than its factorization.

64521556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12156 (or 12132 counting only the distinct ones).

The product of its digits is 36000, while the sum is 34.

The square root of 64521556 is about 8032.5311079385. The cubic root of 64521556 is about 401.0836366779.

It can be divided in two parts, 6452 and 1556, that added together give a palindrome (8008).

The spelling of 64521556 in words is "sixty-four million, five hundred twenty-one thousand, five hundred fifty-six".