21971877 has 16 divisors (see below), whose sum is σ = 30689280. Its totient is φ = 13956272.

The previous prime is 21971861. The next prime is 21971881. The reversal of 21971877 is 77817912.

It is a cyclic number.

It is not a de Polignac number, because 21971877 - 2⁴ = 21971861 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21971827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24328 + ... + 25214.

It is an arithmetic number, because the mean of its divisors is an integer number (1918080).

Almost surely, 2^21971877 is an apocalyptic number.

It is an amenable number.

21971877 is a deficient number, since it is larger than the sum of its proper divisors (8717403).

21971877 is a wasteful number, since it uses less digits than its factorization.

21971877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1272.

The product of its digits is 49392, while the sum is 42.

The square root of 21971877 is about 4687.4168792630. The cubic root of 21971877 is about 280.0844855597.

The spelling of 21971877 in words is "twenty-one million, nine hundred seventy-one thousand, eight hundred seventy-seven".