21977811 has 40 divisors (see below), whose sum is σ = 35126784. Its totient is φ = 13662000.

The previous prime is 21977801. The next prime is 21977833. The reversal of 21977811 is 11877912.

It is not a de Polignac number, because 21977811 - 2⁹ = 21977299 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21977801) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 87436 + ... + 87686.

Almost surely, 2^21977811 is an apocalyptic number.

21977811 is a deficient number, since it is larger than the sum of its proper divisors (13148973).

21977811 is a wasteful number, since it uses less digits than its factorization.

21977811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333 (or 324 counting only the distinct ones).

The product of its digits is 7056, while the sum is 36.

The square root of 21977811 is about 4688.0498077559. The cubic root of 21977811 is about 280.1096976636.

The spelling of 21977811 in words is "twenty-one million, nine hundred seventy-seven thousand, eight hundred eleven".