21591126 has 12 divisors (see below), whose sum is σ = 46780812. Its totient is φ = 7197036.

The previous prime is 21591113. The next prime is 21591127. The reversal of 21591126 is 62119512.

It is a self number, because there is not a number n which added to its sum of digits gives 21591126.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21591127) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 599736 + ... + 599771.

It is an arithmetic number, because the mean of its divisors is an integer number (3898401).

Almost surely, 2^21591126 is an apocalyptic number.

21591126 is an abundant number, since it is smaller than the sum of its proper divisors (25189686).

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

21591126 is a wasteful number, since it uses less digits than its factorization.

21591126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1199515 (or 1199512 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 21591126 is about 4646.6252269793. The cubic root of 21591126 is about 278.4571864045.

The spelling of 21591126 in words is "twenty-one million, five hundred ninety-one thousand, one hundred twenty-six".