21151790 has 32 divisors (see below), whose sum is σ = 42665184. Its totient is φ = 7482240.

The previous prime is 21151787. The next prime is 21151799. The reversal of 21151790 is 9715112.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151799) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1472 + ... + 6668.

It is an arithmetic number, because the mean of its divisors is an integer number (1333287).

Almost surely, 2^21151790 is an apocalyptic number.

21151790 is an abundant number, since it is smaller than the sum of its proper divisors (21513394).

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

21151790 is a wasteful number, since it uses less digits than its factorization.

21151790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5252.

The product of its (nonzero) digits is 630, while the sum is 26.

The square root of 21151790 is about 4599.1075221177. The cubic root of 21151790 is about 276.5555480287. Note that the first 4 decimals are identical.

The spelling of 21151790 in words is "twenty-one million, one hundred fifty-one thousand, seven hundred ninety".