64647458021 has 2 divisors, whose sum is σ = 64647458022. Its totient is φ = 64647458020.

The previous prime is 64647458017. The next prime is 64647458053. The reversal of 64647458021 is 12085474646.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39267781921 + 25379676100 = 198161^2 + 159310^2 .

It is a cyclic number.

It is not a de Polignac number, because 64647458021 - 2² = 64647458017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64647455021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32323729010 + 32323729011.

It is an arithmetic number, because the mean of its divisors is an integer number (32323729011).

Almost surely, 2^64647458021 is an apocalyptic number.

It is an amenable number.

64647458021 is a deficient number, since it is larger than the sum of its proper divisors (1).

64647458021 is an equidigital number, since it uses as much as digits as its factorization.

64647458021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1290240, while the sum is 47.

The spelling of 64647458021 in words is "sixty-four billion, six hundred forty-seven million, four hundred fifty-eight thousand, twenty-one".