21772863 has 12 divisors (see below), whose sum is σ = 35942608. Its totient is φ = 12441600.

The previous prime is 21772853. The next prime is 21772897. The reversal of 21772863 is 36827712.

It is not a de Polignac number, because 21772863 - 2⁸ = 21772607 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 (21772813) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 172738 + ... + 172863.

Almost surely, 2^21772863 is an apocalyptic number.

21772863 is a deficient number, since it is larger than the sum of its proper divisors (14169745).

21772863 is a wasteful number, since it uses less digits than its factorization.

21772863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345614 (or 345611 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 21772863 is about 4666.1400536203. The cubic root of 21772863 is about 279.2362818987.

The spelling of 21772863 in words is "twenty-one million, seven hundred seventy-two thousand, eight hundred sixty-three".