20976779 has 4 divisors (see below), whose sum is σ = 22080840. Its totient is φ = 19872720.

The previous prime is 20976763. The next prime is 20976797. The reversal of 20976779 is 97767902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20976779 - 2⁴ = 20976763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20976719) 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, 552002 + ... + 552039.

It is an arithmetic number, because the mean of its divisors is an integer number (5520210).

Almost surely, 2^20976779 is an apocalyptic number.

20976779 is a deficient number, since it is larger than the sum of its proper divisors (1104061).

20976779 is a wasteful number, since it uses less digits than its factorization.

20976779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104060.

The product of its (nonzero) digits is 333396, while the sum is 47.

The square root of 20976779 is about 4580.0413753590. The cubic root of 20976779 is about 275.7906896915.

The spelling of 20976779 in words is "twenty million, nine hundred seventy-six thousand, seven hundred seventy-nine".