21175000000 has 378 divisors, whose sum is σ = 65980434968. Its totient is φ = 6600000000.

The previous prime is 21174999997. The next prime is 21175000009. The reversal of 21175000000 is 57112.

It is a hoax number, since the sum of its digits (16) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21175000009) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 1924999995 + ... + 1925000005.

Almost surely, 2^21175000000 is an apocalyptic number.

21175000000 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 21175000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32990217484).

21175000000 is an abundant number, since it is smaller than the sum of its proper divisors (44805434968).

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

21175000000 is an frugal number, since it uses more digits than its factorization.

21175000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 25 counting only the distinct ones).

The product of its (nonzero) digits is 70, while the sum is 16.

Adding to 21175000000 its reverse (57112), we get a palindrome (21175057112).

The spelling of 21175000000 in words is "twenty-one billion, one hundred seventy-five million", and thus it is an aban number.