64218921 has 16 divisors (see below), whose sum is σ = 96222336. Its totient is φ = 37800576.

The previous prime is 64218901. The next prime is 64218953. The reversal of 64218921 is 12981246.

It is not a de Polignac number, because 64218921 - 2⁶ = 64218857 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (64218901) 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, 34900 + ... + 36693.

It is an arithmetic number, because the mean of its divisors is an integer number (6013896).

Almost surely, 2^64218921 is an apocalyptic number.

It is an amenable number.

64218921 is a deficient number, since it is larger than the sum of its proper divisors (32003415).

64218921 is a wasteful number, since it uses less digits than its factorization.

64218921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71632.

The product of its digits is 6912, while the sum is 33.

The square root of 64218921 is about 8013.6708816871. The cubic root of 64218921 is about 400.4555663679.

The spelling of 64218921 in words is "sixty-four million, two hundred eighteen thousand, nine hundred twenty-one".