64259981 has 2 divisors, whose sum is σ = 64259982. Its totient is φ = 64259980.

The previous prime is 64259977. The next prime is 64259989. The reversal of 64259981 is 18995246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60684100 + 3575881 = 7790^2 + 1891^2 .

It is a cyclic number.

It is not a de Polignac number, because 64259981 - 2² = 64259977 is a prime.

It is a super-2 number, since 2×64259981² = 8258690316240722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64259989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32129990 + 32129991.

It is an arithmetic number, because the mean of its divisors is an integer number (32129991).

Almost surely, 2^64259981 is an apocalyptic number.

It is an amenable number.

64259981 is a deficient number, since it is larger than the sum of its proper divisors (1).

64259981 is an equidigital number, since it uses as much as digits as its factorization.

64259981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 44.

The square root of 64259981 is about 8016.2323444371. The cubic root of 64259981 is about 400.5408953342.

The spelling of 64259981 in words is "sixty-four million, two hundred fifty-nine thousand, nine hundred eighty-one".