21890736 has 200 divisors, whose sum is σ = 76820480. Its totient is φ = 5878656.

The previous prime is 21890723. The next prime is 21890773. The reversal of 21890736 is 63709812.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21890736.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 172305 + ... + 172431.

Almost surely, 2^21890736 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 21890736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38410240).

21890736 is an abundant number, since it is smaller than the sum of its proper divisors (54929744).

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

21890736 is a wasteful number, since it uses less digits than its factorization.

21890736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21890736 is about 4678.7536802016. The cubic root of 21890736 is about 279.7392811194.

The spelling of 21890736 in words is "twenty-one million, eight hundred ninety thousand, seven hundred thirty-six".