21512963 has 8 divisors (see below), whose sum is σ = 21911232. Its totient is φ = 21117096.

The previous prime is 21512957. The next prime is 21512969. The reversal of 21512963 is 36921512.

It is an interprime number because it is at equal distance from previous prime (21512957) and next prime (21512969).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21512963 - 2¹² = 21508867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21512969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36356 + ... + 36942.

It is an arithmetic number, because the mean of its divisors is an integer number (2738904).

Almost surely, 2^21512963 is an apocalyptic number.

21512963 is a deficient number, since it is larger than the sum of its proper divisors (398269).

21512963 is an equidigital number, since it uses as much as digits as its factorization.

21512963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201.

The product of its digits is 3240, while the sum is 29.

The square root of 21512963 is about 4638.2068733510. The cubic root of 21512963 is about 278.1207616743.

The spelling of 21512963 in words is "twenty-one million, five hundred twelve thousand, nine hundred sixty-three".