64720531 has 2 divisors, whose sum is σ = 64720532. Its totient is φ = 64720530.

The previous prime is 64720471. The next prime is 64720543. The reversal of 64720531 is 13502746.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 64720531 - 2²³ = 56331923 is a prime.

It is a super-2 number, since 2×64720531² = 8377494265843922, which contains 22 as substring.

It is equal to p_3825073 and since 64720531 and 3825073 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64720531.

It is not a weakly prime, because it can be changed into another prime (64720561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32360265 + 32360266.

It is an arithmetic number, because the mean of its divisors is an integer number (32360266).

Almost surely, 2^64720531 is an apocalyptic number.

64720531 is a deficient number, since it is larger than the sum of its proper divisors (1).

64720531 is an equidigital number, since it uses as much as digits as its factorization.

64720531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 64720531 is about 8044.9071467606. The cubic root of 64720531 is about 401.4955079219.

The spelling of 64720531 in words is "sixty-four million, seven hundred twenty thousand, five hundred thirty-one".