64440631 has 2 divisors, whose sum is σ = 64440632. Its totient is φ = 64440630.

The previous prime is 64440613. The next prime is 64440637. The reversal of 64440631 is 13604446.

It is a happy number.

Together with previous prime (64440613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 64440631 - 2⁹ = 64440119 is a prime.

It is a super-2 number, since 2×64440631² = 8305189847356322, which contains 22 as substring.

It is equal to p_3809611 and since 64440631 and 3809611 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 64440631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64440637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32220315 + 32220316.

It is an arithmetic number, because the mean of its divisors is an integer number (32220316).

Almost surely, 2^64440631 is an apocalyptic number.

64440631 is a deficient number, since it is larger than the sum of its proper divisors (1).

64440631 is an equidigital number, since it uses as much as digits as its factorization.

64440631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 64440631 is about 8027.4921986882. The cubic root of 64440631 is about 400.9158825473.

The spelling of 64440631 in words is "sixty-four million, four hundred forty thousand, six hundred thirty-one".