21525051 has 8 divisors (see below), whose sum is σ = 29063680. Its totient is φ = 14168232.

The previous prime is 21525017. The next prime is 21525059. The reversal of 21525051 is 15052512.

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

It is not a de Polignac number, because 21525051 - 2⁹ = 21524539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525059) 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, 45175 + ... + 45648.

It is an arithmetic number, because the mean of its divisors is an integer number (3632960).

Almost surely, 2^21525051 is an apocalyptic number.

21525051 is a deficient number, since it is larger than the sum of its proper divisors (7538629).

21525051 is an equidigital number, since it uses as much as digits as its factorization.

21525051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90905.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 21525051 is about 4639.5097801384. The cubic root of 21525051 is about 278.1728433623.

Adding to 21525051 its reverse (15052512), we get a palindrome (36577563).

The spelling of 21525051 in words is "twenty-one million, five hundred twenty-five thousand, fifty-one".