21989201520 has 640 divisors, whose sum is σ = 84774574080. Its totient is φ = 4638965760.

The previous prime is 21989201461. The next prime is 21989201557. The reversal of 21989201520 is 2510298912.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 70252884 + ... + 70253196.

It is an arithmetic number, because the mean of its divisors is an integer number (132460272).

Almost surely, 2^21989201520 is an apocalyptic number.

21989201520 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 21989201520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42387287040).

21989201520 is an abundant number, since it is smaller than the sum of its proper divisors (62785372560).

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

21989201520 is a wasteful number, since it uses less digits than its factorization.

21989201520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465 (or 459 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 39.

The spelling of 21989201520 in words is "twenty-one billion, nine hundred eighty-nine million, two hundred one thousand, five hundred twenty".