21953960 has 96 divisors (see below), whose sum is σ = 60082560. Its totient is φ = 7185024.

The previous prime is 21953923. The next prime is 21953963. The reversal of 21953960 is 6935912.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 21953960.

It is not an unprimeable number, because it can be changed into a prime (21953963) 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, 44837 + ... + 45323.

It is an arithmetic number, because the mean of its divisors is an integer number (625860).

Almost surely, 2^21953960 is an apocalyptic number.

21953960 is a gapful number since it is divisible by the number (20) 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 21953960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30041280).

21953960 is an abundant number, since it is smaller than the sum of its proper divisors (38128600).

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

21953960 is a wasteful number, since it uses less digits than its factorization.

21953960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535 (or 524 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21953960 is about 4685.5053089288. The cubic root of 21953960 is about 280.0083330853.

The spelling of 21953960 in words is "twenty-one million, nine hundred fifty-three thousand, nine hundred sixty".