21972463 has 4 divisors (see below), whose sum is σ = 22118128. Its totient is φ = 21826800.

The previous prime is 21972451. The next prime is 21972469. The reversal of 21972463 is 36427912.

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

It is a cyclic number.

It is not a de Polignac number, because 21972463 - 2⁹ = 21971951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21972469) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72606 + ... + 72907.

It is an arithmetic number, because the mean of its divisors is an integer number (5529532).

Almost surely, 2^21972463 is an apocalyptic number.

21972463 is a deficient number, since it is larger than the sum of its proper divisors (145665).

21972463 is a wasteful number, since it uses less digits than its factorization.

21972463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145664.

The product of its digits is 18144, while the sum is 34.

The square root of 21972463 is about 4687.4793866213. The cubic root of 21972463 is about 280.0869755313.

The spelling of 21972463 in words is "twenty-one million, nine hundred seventy-two thousand, four hundred sixty-three".