64400989 has 12 divisors (see below), whose sum is σ = 68622876. Its totient is φ = 60412352.

The previous prime is 64400969. The next prime is 64401017. The reversal of 64400989 is 98900446.

It can be written as a sum of positive squares in 2 ways, for example, as 38564100 + 25836889 = 6210^2 + 5083^2 .

It is not a de Polignac number, because 64400989 - 2⁵ = 64400957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64400939) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 26889 + ... + 29185.

It is an arithmetic number, because the mean of its divisors is an integer number (5718573).

Almost surely, 2^64400989 is an apocalyptic number.

It is an amenable number.

64400989 is a deficient number, since it is larger than the sum of its proper divisors (4221887).

64400989 is a wasteful number, since it uses less digits than its factorization.

64400989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2396 (or 2373 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 64400989 is about 8025.0226790957. The cubic root of 64400989 is about 400.8336550909.

The spelling of 64400989 in words is "sixty-four million, four hundred thousand, nine hundred eighty-nine".