20397581000 has 64 divisors (see below), whose sum is σ = 47957045760. Its totient is φ = 8120280000.

The previous prime is 20397580963. The next prime is 20397581047. The reversal of 20397581000 is 18579302.

It is a super-2 number, since 2×20397581000² (a number of 21 digits) contains 22 as substring.

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, 162665 + ... + 259335.

It is an arithmetic number, because the mean of its divisors is an integer number (749328840).

Almost surely, 2^20397581000 is an apocalyptic number.

20397581000 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 20397581000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23978522880).

20397581000 is an abundant number, since it is smaller than the sum of its proper divisors (27559464760).

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

20397581000 is a wasteful number, since it uses less digits than its factorization.

20397581000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96903 (or 96889 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The spelling of 20397581000 in words is "twenty billion, three hundred ninety-seven million, five hundred eighty-one thousand".