64979721 has 9 divisors (see below), whose sum is σ = 93894541. Its totient is φ = 43303692.

The previous prime is 64979671. The next prime is 64979723. The reversal of 64979721 is 12797946.

The square root of 64979721 is 8061.

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

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 64979721 - 2¹¹ = 64977673 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (64979723) 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, 22840 + ... + 25526.

Almost surely, 2^64979721 is an apocalyptic number.

64979721 is the 8061-st square number.

64979721 is the 4031-st centered octagonal number.

It is an amenable number.

64979721 is a deficient number, since it is larger than the sum of its proper divisors (28914820).

64979721 is an frugal number, since it uses more digits than its factorization.

64979721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380 (or 2690 counting only the distinct ones).

The product of its digits is 190512, while the sum is 45.

The cubic root of 64979721 is about 402.0307580238.

The spelling of 64979721 in words is "sixty-four million, nine hundred seventy-nine thousand, seven hundred twenty-one".