64971661 has 2 divisors, whose sum is σ = 64971662. Its totient is φ = 64971660.

The previous prime is 64971631. The next prime is 64971703. The reversal of 64971661 is 16617946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53377636 + 11594025 = 7306^2 + 3405^2 .

It is a cyclic number.

It is not a de Polignac number, because 64971661 - 2²¹ = 62874509 is a prime.

It is a super-3 number, since 3×64971661³ (a number of 24 digits) contains 333 as substring.

It is a Chen prime.

It is the 8061-st Hogben number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64971611) by changing a digit.

It is a nontrivial repunit in base 8060.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32485830 + 32485831.

It is an arithmetic number, because the mean of its divisors is an integer number (32485831).

Almost surely, 2^64971661 is an apocalyptic number.

It is an amenable number.

64971661 is a deficient number, since it is larger than the sum of its proper divisors (1).

64971661 is an equidigital number, since it uses as much as digits as its factorization.

64971661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 40.

The square root of 64971661 is about 8060.5000465232. The cubic root of 64971661 is about 402.0141348792.

The spelling of 64971661 in words is "sixty-four million, nine hundred seventy-one thousand, six hundred sixty-one".