20777879 has 4 divisors (see below), whose sum is σ = 20844576. Its totient is φ = 20711184.

The previous prime is 20777837. The next prime is 20777899. The reversal of 20777879 is 97877702.

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 20777879 - 2¹⁶ = 20712343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20777899) 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, 32879 + ... + 33504.

It is an arithmetic number, because the mean of its divisors is an integer number (5211144).

Almost surely, 2^20777879 is an apocalyptic number.

20777879 is a deficient number, since it is larger than the sum of its proper divisors (66697).

20777879 is an equidigital number, since it uses as much as digits as its factorization.

20777879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66696.

The product of its (nonzero) digits is 345744, while the sum is 47.

The square root of 20777879 is about 4558.2758801986. The cubic root of 20777879 is about 274.9162455686.

The spelling of 20777879 in words is "twenty million, seven hundred seventy-seven thousand, eight hundred seventy-nine".