21988373216640 has 128 divisors (see below), whose sum is σ = 70091056170720. Its totient is φ = 5863305461760.

The previous prime is 21988373216629. The next prime is 21988373216717. The reversal of 21988373216640 is 4661237388912.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45032692 + ... + 45518348.

Almost surely, 2^{21988373216640} is an apocalyptic number.

21988373216640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21988373216640 is an abundant number, since it is smaller than the sum of its proper divisors (48102682954080).

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

21988373216640 is a wasteful number, since it uses less digits than its factorization.

21988373216640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509260 (or 509248 counting only the distinct ones).

The product of its (nonzero) digits is 20901888, while the sum is 60.

The spelling of 21988373216640 in words is "twenty-one trillion, nine hundred eighty-eight billion, three hundred seventy-three million, two hundred sixteen thousand, six hundred forty".