21522501 has 48 divisors (see below), whose sum is σ = 41758080. Its totient is φ = 10316160.

The previous prime is 21522491. The next prime is 21522509. The reversal of 21522501 is 10522512.

It is not a de Polignac number, because 21522501 - 2⁷ = 21522373 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21522509) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7815 + ... + 10203.

It is an arithmetic number, because the mean of its divisors is an integer number (869960).

Almost surely, 2^21522501 is an apocalyptic number.

21522501 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21522501 is a deficient number, since it is larger than the sum of its proper divisors (20235579).

21522501 is a wasteful number, since it uses less digits than its factorization.

21522501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2426 (or 2423 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21522501 is about 4639.2349584818. The cubic root of 21522501 is about 278.1618581965.

The spelling of 21522501 in words is "twenty-one million, five hundred twenty-two thousand, five hundred one".