21825506 has 16 divisors (see below), whose sum is σ = 33679800. Its totient is φ = 10603008.

The previous prime is 21825499. The next prime is 21825521. The reversal of 21825506 is 60552812.

It can be written as a sum of positive squares in 4 ways, for example, as 21077281 + 748225 = 4591^2 + 865^2 .

It is a super-4 number, since 4×21825506⁴ (a number of 30 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10610 + ... + 12498.

Almost surely, 2^21825506 is an apocalyptic number.

21825506 is a deficient number, since it is larger than the sum of its proper divisors (11854294).

21825506 is a wasteful number, since it uses less digits than its factorization.

21825506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2053.

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 21825506 is about 4671.7776060082. Note that the first 3 decimals coincide. The cubic root of 21825506 is about 279.4611490381.

The spelling of 21825506 in words is "twenty-one million, eight hundred twenty-five thousand, five hundred six".