64207921 has 4 divisors (see below), whose sum is σ = 64249200. Its totient is φ = 64166644.

The previous prime is 64207907. The next prime is 64207937. The reversal of 64207921 is 12970246.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12970246 = 2 ⋅6485123.

It is a cyclic number.

It is not a de Polignac number, because 64207921 - 2¹¹ = 64205873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64207981) 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, 18211 + ... + 21448.

It is an arithmetic number, because the mean of its divisors is an integer number (16062300).

Almost surely, 2^64207921 is an apocalyptic number.

It is an amenable number.

64207921 is a deficient number, since it is larger than the sum of its proper divisors (41279).

64207921 is a wasteful number, since it uses less digits than its factorization.

64207921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41278.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 64207921 is about 8012.9845251317. The cubic root of 64207921 is about 400.4327005069.

It can be divided in two parts, 6420 and 7921, that added together give a palindrome (14341).

The spelling of 64207921 in words is "sixty-four million, two hundred seven thousand, nine hundred twenty-one".