21293712 has 80 divisors (see below), whose sum is σ = 66692160. Its totient is φ = 6451200.

The previous prime is 21293711. The next prime is 21293717. The reversal of 21293712 is 21739212.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21293711) 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, 2512 + ... + 6992.

It is an arithmetic number, because the mean of its divisors is an integer number (833652).

Almost surely, 2^21293712 is an apocalyptic number.

21293712 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21293712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33346080).

21293712 is an abundant number, since it is smaller than the sum of its proper divisors (45398448).

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

21293712 is a wasteful number, since it uses less digits than its factorization.

21293712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4509 (or 4497 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21293712 is about 4614.5110250166. The cubic root of 21293712 is about 277.1727039707.

The spelling of 21293712 in words is "twenty-one million, two hundred ninety-three thousand, seven hundred twelve".