20557916 has 6 divisors (see below), whose sum is σ = 35976360. Its totient is φ = 10278956.

The previous prime is 20557909. The next prime is 20557919. The reversal of 20557916 is 61975502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20557919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2569736 + ... + 2569743.

It is an arithmetic number, because the mean of its divisors is an integer number (5996060).

Almost surely, 2^20557916 is an apocalyptic number.

It is an amenable number.

20557916 is a deficient number, since it is larger than the sum of its proper divisors (15418444).

20557916 is a wasteful number, since it uses less digits than its factorization.

20557916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5139483 (or 5139481 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 20557916 is about 4534.0838104296. The cubic root of 20557916 is about 273.9426771946.

The spelling of 20557916 in words is "twenty million, five hundred fifty-seven thousand, nine hundred sixteen".