21739997000 has 64 divisors (see below), whose sum is σ = 50909040000. Its totient is φ = 8689598400.

The previous prime is 21739996987. The next prime is 21739997029. The reversal of 21739997000 is 79993712.

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, 1491749 + ... + 1506251.

It is an arithmetic number, because the mean of its divisors is an integer number (795453750).

Almost surely, 2^21739997000 is an apocalyptic number.

21739997000 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 21739997000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25454520000).

21739997000 is an abundant number, since it is smaller than the sum of its proper divisors (29169043000).

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

21739997000 is a wasteful number, since it uses less digits than its factorization.

21739997000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16023 (or 16009 counting only the distinct ones).

The product of its (nonzero) digits is 214326, while the sum is 47.

The spelling of 21739997000 in words is "twenty-one billion, seven hundred thirty-nine million, nine hundred ninety-seven thousand".