21071751900 has 72 divisors (see below), whose sum is σ = 61004522544. Its totient is φ = 5615731200.

The previous prime is 21071751851. The next prime is 21071751901. The reversal of 21071751900 is 915717012.

It is a super-2 number, since 2×21071751900² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071751901) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 495894 + ... + 536706.

Almost surely, 2^21071751900 is an apocalyptic number.

21071751900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21071751900 is an abundant number, since it is smaller than the sum of its proper divisors (39932770644).

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

21071751900 is a wasteful number, since it uses less digits than its factorization.

21071751900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42551 (or 42544 counting only the distinct ones).

The product of its (nonzero) digits is 4410, while the sum is 33.

The spelling of 21071751900 in words is "twenty-one billion, seventy-one million, seven hundred fifty-one thousand, nine hundred".