21712963 has 2 divisors, whose sum is σ = 21712964. Its totient is φ = 21712962.

The previous prime is 21712949. The next prime is 21712973. The reversal of 21712963 is 36921712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21712963 - 2⁵ = 21712931 is a prime.

It is not a weakly prime, because it can be changed into another prime (21712973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856481 + 10856482.

It is an arithmetic number, because the mean of its divisors is an integer number (10856482).

Almost surely, 2^21712963 is an apocalyptic number.

21712963 is a deficient number, since it is larger than the sum of its proper divisors (1).

21712963 is an equidigital number, since it uses as much as digits as its factorization.

21712963 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 31.

The square root of 21712963 is about 4659.7170514957. The cubic root of 21712963 is about 278.9799748392.

The spelling of 21712963 in words is "twenty-one million, seven hundred twelve thousand, nine hundred sixty-three".