21071790 has 24 divisors (see below), whose sum is σ = 54786888. Its totient is φ = 5619120.

The previous prime is 21071773. The next prime is 21071797. The reversal of 21071790 is 9717012.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071797) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116976 + ... + 117155.

It is an arithmetic number, because the mean of its divisors is an integer number (2282787).

Almost surely, 2^21071790 is an apocalyptic number.

21071790 is an abundant number, since it is smaller than the sum of its proper divisors (33715098).

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

21071790 is a wasteful number, since it uses less digits than its factorization.

21071790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234144 (or 234141 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 21071790 is about 4590.4019431854. The cubic root of 21071790 is about 276.2064460454.

The spelling of 21071790 in words is "twenty-one million, seventy-one thousand, seven hundred ninety".