21525806 has 8 divisors (see below), whose sum is σ = 32415120. Its totient is φ = 10720768.

The previous prime is 21525793. The next prime is 21525853. The reversal of 21525806 is 60852512.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20426 + ... + 21453.

It is an arithmetic number, because the mean of its divisors is an integer number (4051890).

Almost surely, 2^21525806 is an apocalyptic number.

21525806 is a deficient number, since it is larger than the sum of its proper divisors (10889314).

21525806 is a wasteful number, since it uses less digits than its factorization.

21525806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42138.

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

The square root of 21525806 is about 4639.5911457800. The cubic root of 21525806 is about 278.1760956665.

The spelling of 21525806 in words is "twenty-one million, five hundred twenty-five thousand, eight hundred six".