21450975 has 72 divisors (see below), whose sum is σ = 44528400. Its totient is φ = 9031680.

The previous prime is 21450971. The next prime is 21451007. The reversal of 21450975 is 57905412.

It is not a de Polignac number, because 21450975 - 2² = 21450971 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450971) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 47551 + ... + 47999.

It is an arithmetic number, because the mean of its divisors is an integer number (618450).

Almost surely, 2^21450975 is an apocalyptic number.

21450975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21450975 is an abundant number, since it is smaller than the sum of its proper divisors (23077425).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21450975 is a wasteful number, since it uses less digits than its factorization.

21450975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 33.

The square root of 21450975 is about 4631.5197289875. The cubic root of 21450975 is about 277.8533766087.

The spelling of 21450975 in words is "twenty-one million, four hundred fifty thousand, nine hundred seventy-five".