64400436 has 18 divisors (see below), whose sum is σ = 162790082. Its totient is φ = 21466800.

The previous prime is 64400419. The next prime is 64400449. The reversal of 64400436 is 63400446.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 63297936 + 1102500 = 7956^2 + 1050^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 894415 + ... + 894486.

Almost surely, 2^64400436 is an apocalyptic number.

It is an amenable number.

64400436 is an abundant number, since it is smaller than the sum of its proper divisors (98389646).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64400436 is a wasteful number, since it uses less digits than its factorization.

64400436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1788911 (or 1788906 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

The square root of 64400436 is about 8024.9882242904. The cubic root of 64400436 is about 400.8325077916.

The spelling of 64400436 in words is "sixty-four million, four hundred thousand, four hundred thirty-six".