21980263 has 4 divisors (see below), whose sum is σ = 21992320. Its totient is φ = 21968208.

The previous prime is 21980243. The next prime is 21980281. The reversal of 21980263 is 36208912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21980263 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 (21980243) 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, 2670 + ... + 7147.

It is an arithmetic number, because the mean of its divisors is an integer number (5498080).

Almost surely, 2^21980263 is an apocalyptic number.

21980263 is a deficient number, since it is larger than the sum of its proper divisors (12057).

21980263 is an equidigital number, since it uses as much as digits as its factorization.

21980263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12056.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21980263 is about 4688.3113164550. The cubic root of 21980263 is about 280.1201142824.

The spelling of 21980263 in words is "twenty-one million, nine hundred eighty thousand, two hundred sixty-three".