64567829938921 has 9 divisors (see below), whose sum is σ = 64967699672631. Its totient is φ = 64170406546272.

The previous prime is 64567829938889. The next prime is 64567829938933. The reversal of 64567829938921 is 12983992876546.

The square root of 64567829938921 is 8035411.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1626836475625 + 62940993463296 = 1275475^2 + 7933536^2 .

It is not a de Polignac number, because 64567829938921 - 2⁵ = 64567829938889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64567829938951) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1309747345 + ... + 1309796641.

It is an arithmetic number, because the mean of its divisors is an integer number (7218633296959).

Almost surely, 2^{64567829938921} is an apocalyptic number.

64567829938921 is the 8035411-st square number.

64567829938921 is the 4017706-th centered octagonal number.

It is an amenable number.

64567829938921 is a deficient number, since it is larger than the sum of its proper divisors (399869733710).

64567829938921 is an frugal number, since it uses more digits than its factorization.

64567829938921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98920 (or 49460 counting only the distinct ones).

The product of its digits is 2821754880, while the sum is 79.

The spelling of 64567829938921 in words is "sixty-four trillion, five hundred sixty-seven billion, eight hundred twenty-nine million, nine hundred thirty-eight thousand, nine hundred twenty-one".