64899920 has 40 divisors (see below), whose sum is σ = 152973096. Its totient is φ = 25602048.

The previous prime is 64899907. The next prime is 64899937. The reversal of 64899920 is 2999846.

It can be written as a sum of positive squares in 4 ways, for example, as 784 + 64899136 = 28^2 + 8056^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 284 + ... + 11396.

Almost surely, 2^64899920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64899920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76486548).

64899920 is an abundant number, since it is smaller than the sum of its proper divisors (88073176).

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

64899920 is a wasteful number, since it uses less digits than its factorization.

64899920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11199 (or 11193 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 47.

The square root of 64899920 is about 8056.0486592374. The cubic root of 64899920 is about 401.8661138426.

The spelling of 64899920 in words is "sixty-four million, eight hundred ninety-nine thousand, nine hundred twenty".