21540983 has 2 divisors, whose sum is σ = 21540984. Its totient is φ = 21540982.

The previous prime is 21540947. The next prime is 21541019. The reversal of 21540983 is 38904512.

It is a balanced prime because it is at equal distance from previous prime (21540947) and next prime (21541019).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21540983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21540083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770491 + 10770492.

It is an arithmetic number, because the mean of its divisors is an integer number (10770492).

Almost surely, 2^21540983 is an apocalyptic number.

21540983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540983 is an equidigital number, since it uses as much as digits as its factorization.

21540983 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 21540983 is about 4641.2264542899. The cubic root of 21540983 is about 278.2414573191.

The spelling of 21540983 in words is "twenty-one million, five hundred forty thousand, nine hundred eighty-three".