21977109 has 72 divisors (see below), whose sum is σ = 42262080. Its totient is φ = 11048400.

The previous prime is 21977101. The next prime is 21977113. The reversal of 21977109 is 90177912.

It is not a de Polignac number, because 21977109 - 2³ = 21977101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977101) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 708924 + ... + 708954.

Almost surely, 2^21977109 is an apocalyptic number.

It is an amenable number.

21977109 is a deficient number, since it is larger than the sum of its proper divisors (20284971).

21977109 is a wasteful number, since it uses less digits than its factorization.

21977109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 21977109 is about 4687.9749359398. The cubic root of 21977109 is about 280.1067152752.

The spelling of 21977109 in words is "twenty-one million, nine hundred seventy-seven thousand, one hundred nine".