64610721 has 24 divisors (see below), whose sum is σ = 107390400. Its totient is φ = 36667296.

The previous prime is 64610701. The next prime is 64610743. The reversal of 64610721 is 12701646.

64610721 is a `hidden beast` number, since 646 + 10 + 7 + 2 + 1 = 666.

It is not a de Polignac number, because 64610721 - 2⁷ = 64610593 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64610701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5946 + ... + 12828.

It is an arithmetic number, because the mean of its divisors is an integer number (4474600).

Almost surely, 2^64610721 is an apocalyptic number.

It is an amenable number.

64610721 is a deficient number, since it is larger than the sum of its proper divisors (42779679).

64610721 is a wasteful number, since it uses less digits than its factorization.

64610721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7045 (or 7042 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 64610721 is about 8038.0794347904. The cubic root of 64610721 is about 401.2683096428.

The spelling of 64610721 in words is "sixty-four million, six hundred ten thousand, seven hundred twenty-one".