20516664 has 64 divisors (see below), whose sum is σ = 59270400. Its totient is φ = 5796864.

The previous prime is 20516609. The next prime is 20516681. The reversal of 20516664 is 46661502.

It is a congruent number.

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, 15667 + ... + 16925.

It is an arithmetic number, because the mean of its divisors is an integer number (926100).

Almost surely, 2^20516664 is an apocalyptic number.

20516664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20516664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29635200).

20516664 is an abundant number, since it is smaller than the sum of its proper divisors (38753736).

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

20516664 is a wasteful number, since it uses less digits than its factorization.

20516664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1372 (or 1368 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20516664 is about 4529.5324262003. The cubic root of 20516664 is about 273.7593212147.

The spelling of 20516664 in words is "twenty million, five hundred sixteen thousand, six hundred sixty-four".