21953016 has 24 divisors (see below), whose sum is σ = 59456280. Its totient is φ = 7317648.

The previous prime is 21953011. The next prime is 21953033. The reversal of 21953016 is 61035912.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×21953016² = 963869822992512, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21953011) 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, 152380 + ... + 152523.

It is an arithmetic number, because the mean of its divisors is an integer number (2477345).

Almost surely, 2^21953016 is an apocalyptic number.

It is an amenable number.

21953016 is an abundant number, since it is smaller than the sum of its proper divisors (37503264).

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

21953016 is a wasteful number, since it uses less digits than its factorization.

21953016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304915 (or 304908 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21953016 is about 4685.4045716459. The cubic root of 21953016 is about 280.0043196612.

Adding to 21953016 its reverse (61035912), we get a palindrome (82988928).

It can be divided in two parts, 219 and 53016, that added together give a palindrome (53235).

The spelling of 21953016 in words is "twenty-one million, nine hundred fifty-three thousand, sixteen".