21021294 has 48 divisors (see below), whose sum is σ = 49379328. Its totient is φ = 5948208.

The previous prime is 21021293. The next prime is 21021323. The reversal of 21021294 is 49212012.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21021294.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021293) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37057 + ... + 37619.

It is an arithmetic number, because the mean of its divisors is an integer number (1028736).

Almost surely, 2^21021294 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021294, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24689664).

21021294 is an abundant number, since it is smaller than the sum of its proper divisors (28358034).

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

21021294 is a wasteful number, since it uses less digits than its factorization.

21021294 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709 (or 702 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21021294 is about 4584.8984721584. The cubic root of 21021294 is about 275.9856377740.

The spelling of 21021294 in words is "twenty-one million, twenty-one thousand, two hundred ninety-four".