21988373216639 has 32 divisors (see below), whose sum is σ = 23189504437440. Its totient is φ = 20818917504000.

The previous prime is 21988373216629. The next prime is 21988373216717. The reversal of 21988373216639 is 93661237388912.

It is a cyclic number.

It is not a de Polignac number, because 21988373216639 - 2¹² = 21988373212543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21988373216629) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3728735939 + ... + 3728741835.

It is an arithmetic number, because the mean of its divisors is an integer number (724672013670).

Almost surely, 2^{21988373216639} is an apocalyptic number.

21988373216639 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21988373216639 is a deficient number, since it is larger than the sum of its proper divisors (1201131220801).

21988373216639 is a wasteful number, since it uses less digits than its factorization.

21988373216639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12011.

The product of its digits is 141087744, while the sum is 68.

The spelling of 21988373216639 in words is "twenty-one trillion, nine hundred eighty-eight billion, three hundred seventy-three million, two hundred sixteen thousand, six hundred thirty-nine".