21291246 has 12 divisors (see below), whose sum is σ = 46131072. Its totient is φ = 7097076.

The previous prime is 21291239. The next prime is 21291247. The reversal of 21291246 is 64219212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21291247) 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, 591406 + ... + 591441.

It is an arithmetic number, because the mean of its divisors is an integer number (3844256).

Almost surely, 2^21291246 is an apocalyptic number.

21291246 is an abundant number, since it is smaller than the sum of its proper divisors (24839826).

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

21291246 is a wasteful number, since it uses less digits than its factorization.

21291246 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1182855 (or 1182852 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21291246 is about 4614.2438167050. The cubic root of 21291246 is about 277.1620038749.

It can be divided in two parts, 2129 and 1246, that added together give a cube (3375 = 15³).

The spelling of 21291246 in words is "twenty-one million, two hundred ninety-one thousand, two hundred forty-six".