21528963 has 16 divisors (see below), whose sum is σ = 32054400. Its totient is φ = 14280840.

The previous prime is 21528937. The next prime is 21529003. The reversal of 21528963 is 36982512.

It is not a de Polignac number, because 21528963 - 2⁸ = 21528707 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21528863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3808 + ... + 7586.

It is an arithmetic number, because the mean of its divisors is an integer number (2003400).

Almost surely, 2^21528963 is an apocalyptic number.

21528963 is a deficient number, since it is larger than the sum of its proper divisors (10525437).

21528963 is a wasteful number, since it uses less digits than its factorization.

21528963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3999 (or 3993 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21528963 is about 4639.9313572509. The cubic root of 21528963 is about 278.1896942127.

The spelling of 21528963 in words is "twenty-one million, five hundred twenty-eight thousand, nine hundred sixty-three".