21125090 has 32 divisors (see below), whose sum is σ = 44388864. Its totient is φ = 7087680.

The previous prime is 21125087. The next prime is 21125107. The reversal of 21125090 is 9052112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80 + ... + 6500.

It is an arithmetic number, because the mean of its divisors is an integer number (1387152).

Almost surely, 2^21125090 is an apocalyptic number.

21125090 is an abundant number, since it is smaller than the sum of its proper divisors (23263774).

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

21125090 is a wasteful number, since it uses less digits than its factorization.

21125090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6482.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21125090 is about 4596.2038684114. The cubic root of 21125090 is about 276.4391332591.

The spelling of 21125090 in words is "twenty-one million, one hundred twenty-five thousand, ninety".