64657661 has 4 divisors (see below), whose sum is σ = 66743424. Its totient is φ = 62571900.

The previous prime is 64657651. The next prime is 64657667. The reversal of 64657661 is 16675646.

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 64657661 - 2⁶ = 64657597 is a prime.

It is a super-2 number, since 2×64657661² = 8361226251981842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64657667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1042835 + ... + 1042896.

It is an arithmetic number, because the mean of its divisors is an integer number (16685856).

Almost surely, 2^64657661 is an apocalyptic number.

It is an amenable number.

64657661 is a deficient number, since it is larger than the sum of its proper divisors (2085763).

64657661 is a wasteful number, since it uses less digits than its factorization.

64657661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085762.

The product of its digits is 181440, while the sum is 41.

The square root of 64657661 is about 8040.9987563735. The cubic root of 64657661 is about 401.3654605730.

The spelling of 64657661 in words is "sixty-four million, six hundred fifty-seven thousand, six hundred sixty-one".