21977291 has 8 divisors (see below), whose sum is σ = 25208544. Its totient is φ = 18768960.

The previous prime is 21977279. The next prime is 21977299. The reversal of 21977291 is 19277912.

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

It is not a de Polignac number, because 21977291 - 2²² = 17782987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21977299) 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, 3620 + ... + 7553.

It is an arithmetic number, because the mean of its divisors is an integer number (3151068).

Almost surely, 2^21977291 is an apocalyptic number.

21977291 is a deficient number, since it is larger than the sum of its proper divisors (3231253).

21977291 is a wasteful number, since it uses less digits than its factorization.

21977291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11461.

The product of its digits is 15876, while the sum is 38.

The square root of 21977291 is about 4687.9943472662. The cubic root of 21977291 is about 280.1074884931.

The spelling of 21977291 in words is "twenty-one million, nine hundred seventy-seven thousand, two hundred ninety-one".