20977784 has 16 divisors (see below), whose sum is σ = 39534000. Its totient is φ = 10435392.

The previous prime is 20977783. The next prime is 20977799. The reversal of 20977784 is 48777902.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20977783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4997 + ... + 8180.

It is an arithmetic number, because the mean of its divisors is an integer number (2470875).

Almost surely, 2^20977784 is an apocalyptic number.

It is an amenable number.

20977784 is a deficient number, since it is larger than the sum of its proper divisors (18556216).

20977784 is a wasteful number, since it uses less digits than its factorization.

20977784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13382 (or 13378 counting only the distinct ones).

The product of its (nonzero) digits is 197568, while the sum is 44.

The square root of 20977784 is about 4580.1510892109. The cubic root of 20977784 is about 275.7950940095.

The spelling of 20977784 in words is "twenty million, nine hundred seventy-seven thousand, seven hundred eighty-four".