21974291 has 4 divisors (see below), whose sum is σ = 22176000. Its totient is φ = 21772584.

The previous prime is 21974273. The next prime is 21974299. The reversal of 21974291 is 19247912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21974291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21974299) 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 3 ways as a sum of consecutive naturals, for example, 100691 + ... + 100908.

It is an arithmetic number, because the mean of its divisors is an integer number (5544000).

Almost surely, 2^21974291 is an apocalyptic number.

21974291 is a deficient number, since it is larger than the sum of its proper divisors (201709).

21974291 is a wasteful number, since it uses less digits than its factorization.

21974291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201708.

The product of its digits is 9072, while the sum is 35.

The square root of 21974291 is about 4687.6743700901. The cubic root of 21974291 is about 280.0947425985.

The spelling of 21974291 in words is "twenty-one million, nine hundred seventy-four thousand, two hundred ninety-one".