21252894 has 48 divisors (see below), whose sum is σ = 47136432. Its totient is φ = 6349824.

The previous prime is 21252893. The next prime is 21252899. The reversal of 21252894 is 49825212.

21252894 = 12² + 13² + ... + 399².

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 219054 + ... + 219150.

It is an arithmetic number, because the mean of its divisors is an integer number (982009).

Almost surely, 2^21252894 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21252894, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23568216).

21252894 is an abundant number, since it is smaller than the sum of its proper divisors (25883538).

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

21252894 is a wasteful number, since it uses less digits than its factorization.

21252894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 168 counting only the distinct ones).

The product of its digits is 11520, while the sum is 33.

The square root of 21252894 is about 4610.0861163323. The cubic root of 21252894 is about 276.9954862050.

The spelling of 21252894 in words is "twenty-one million, two hundred fifty-two thousand, eight hundred ninety-four".