64642440 has 64 divisors (see below), whose sum is σ = 200194560. Its totient is φ = 16680960.

The previous prime is 64642423. The next prime is 64642451. The reversal of 64642440 is 4424646.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 64642398 and 64642407.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4969 + ... + 12408.

It is an arithmetic number, because the mean of its divisors is an integer number (3128040).

Almost surely, 2^64642440 is an apocalyptic number.

64642440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

64642440 is an abundant number, since it is smaller than the sum of its proper divisors (135552120).

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

64642440 is a wasteful number, since it uses less digits than its factorization.

64642440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17422 (or 17418 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The square root of 64642440 is about 8040.0522386363. The cubic root of 64642440 is about 401.3339630777. Note that the first 3 decimals are identical.

The spelling of 64642440 in words is "sixty-four million, six hundred forty-two thousand, four hundred forty".