21630196728 has 96 divisors (see below), whose sum is σ = 69861542400. Its totient is φ = 5911354944.

The previous prime is 21630196723. The next prime is 21630196793. The reversal of 21630196728 is 82769103612.

21630196728 is a `hidden beast` number, since 2 + 1 + 630 + 1 + 9 + 6 + 7 + 2 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630196723) 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, 921388 + ... + 944571.

It is an arithmetic number, because the mean of its divisors is an integer number (727724400).

Almost surely, 2^21630196728 is an apocalyptic number.

21630196728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21630196728 is an abundant number, since it is smaller than the sum of its proper divisors (48231345672).

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

21630196728 is a wasteful number, since it uses less digits than its factorization.

21630196728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1866001 (or 1865994 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 21630196728 in words is "twenty-one billion, six hundred thirty million, one hundred ninety-six thousand, seven hundred twenty-eight".