21988789731 has 12 divisors (see below), whose sum is σ = 31769878608. Its totient is φ = 14655365424.

The previous prime is 21988789721. The next prime is 21988789747. The reversal of 21988789731 is 13798788912.

It is not a de Polignac number, because 21988789731 - 2¹⁰ = 21988788707 is a prime.

It is a super-2 number, since 2×21988789731² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21988789721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 282375 + ... + 351728.

It is an arithmetic number, because the mean of its divisors is an integer number (2647489884).

Almost surely, 2^21988789731 is an apocalyptic number.

21988789731 is a deficient number, since it is larger than the sum of its proper divisors (9781088877).

21988789731 is a wasteful number, since it uses less digits than its factorization.

21988789731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637962 (or 637959 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 63.

The spelling of 21988789731 in words is "twenty-one billion, nine hundred eighty-eight million, seven hundred eighty-nine thousand, seven hundred thirty-one".