21980777 has 16 divisors (see below), whose sum is σ = 28479360. Its totient is φ = 16474752.

The previous prime is 21980771. The next prime is 21980789. The reversal of 21980777 is 77708912.

It is not a de Polignac number, because 21980777 - 2¹⁰ = 21979753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21980771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4628 + ... + 8085.

It is an arithmetic number, because the mean of its divisors is an integer number (1779960).

Almost surely, 2^21980777 is an apocalyptic number.

It is an amenable number.

21980777 is a deficient number, since it is larger than the sum of its proper divisors (6498583).

21980777 is a wasteful number, since it uses less digits than its factorization.

21980777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12752.

The product of its (nonzero) digits is 49392, while the sum is 41.

The square root of 21980777 is about 4688.3661333134. The cubic root of 21980777 is about 280.1222977658.

The spelling of 21980777 in words is "twenty-one million, nine hundred eighty thousand, seven hundred seventy-seven".