64756021 has 4 divisors (see below), whose sum is σ = 70642944. Its totient is φ = 58869100.

The previous prime is 64756007. The next prime is 64756039. The reversal of 64756021 is 12065746.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64756021 - 2¹⁷ = 64624949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64756091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2943445 + ... + 2943466.

It is an arithmetic number, because the mean of its divisors is an integer number (17660736).

Almost surely, 2^64756021 is an apocalyptic number.

It is an amenable number.

64756021 is a deficient number, since it is larger than the sum of its proper divisors (5886923).

64756021 is a wasteful number, since it uses less digits than its factorization.

64756021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5886922.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 64756021 is about 8047.1125877547. The cubic root of 64756021 is about 401.5688822263.

The spelling of 64756021 in words is "sixty-four million, seven hundred fifty-six thousand, twenty-one".