21890960 has 160 divisors (see below), whose sum is σ = 65329152. Its totient is φ = 6635520.

The previous prime is 21890959. The next prime is 21890987. The reversal of 21890960 is 6909812.

21890960 is nontrivially palindromic in base 6.

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 21890960.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 225632 + ... + 225728.

Almost surely, 2^21890960 is an apocalyptic number.

21890960 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 21890960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32664576).

21890960 is an abundant number, since it is smaller than the sum of its proper divisors (43438192).

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

21890960 is a wasteful number, since it uses less digits than its factorization.

21890960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 21890960 is about 4678.7776181392. Note that the first 3 decimals coincide. The cubic root of 21890960 is about 279.7402352732.

The spelling of 21890960 in words is "twenty-one million, eight hundred ninety thousand, nine hundred sixty".