21953316 has 96 divisors (see below), whose sum is σ = 66705408. Its totient is φ = 5448960.

The previous prime is 21953311. The next prime is 21953333. The reversal of 21953316 is 61335912.

It is not an unprimeable number, because it can be changed into a prime (21953311) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20736 + ... + 21768.

It is an arithmetic number, because the mean of its divisors is an integer number (694848).

Almost surely, 2^21953316 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21953316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33352704).

21953316 is an abundant number, since it is smaller than the sum of its proper divisors (44752092).

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

21953316 is a wasteful number, since it uses less digits than its factorization.

21953316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081 (or 1079 counting only the distinct ones).

The product of its digits is 4860, while the sum is 30.

The square root of 21953316 is about 4685.4365858477. The cubic root of 21953316 is about 280.0055951263.

It can be divided in two parts, 219 and 53316, that added together give a palindrome (53535).

The spelling of 21953316 in words is "twenty-one million, nine hundred fifty-three thousand, three hundred sixteen".