21977157 has 8 divisors (see below), whose sum is σ = 30313440. Its totient is φ = 14146160.

The previous prime is 21977147. The next prime is 21977159. The reversal of 21977157 is 75177912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21977157 - 2¹⁴ = 21960773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977159) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126219 + ... + 126392.

It is an arithmetic number, because the mean of its divisors is an integer number (3789180).

Almost surely, 2^21977157 is an apocalyptic number.

It is an amenable number.

21977157 is a deficient number, since it is larger than the sum of its proper divisors (8336283).

21977157 is a wasteful number, since it uses less digits than its factorization.

21977157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252643.

The product of its digits is 30870, while the sum is 39.

The square root of 21977157 is about 4687.9800554183. The cubic root of 21977157 is about 280.1069192013.

The spelling of 21977157 in words is "twenty-one million, nine hundred seventy-seven thousand, one hundred fifty-seven".