19921685652 has 108 divisors (see below), whose sum is σ = 56310010848. Its totient is φ = 5889436800.

The previous prime is 19921685579. The next prime is 19921685683. The reversal of 19921685652 is 25658612991.

19921685652 is a `hidden beast` number, since 19 + 9 + 2 + 1 + 68 + 565 + 2 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 650713 + ... + 680639.

Almost surely, 2^19921685652 is an apocalyptic number.

19921685652 is a gapful number since it is divisible by the number (12) 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 19921685652, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28155005424).

19921685652 is an abundant number, since it is smaller than the sum of its proper divisors (36388325196).

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

19921685652 is a wasteful number, since it uses less digits than its factorization.

19921685652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30030 (or 29984 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 54.

The spelling of 19921685652 in words is "nineteen billion, nine hundred twenty-one million, six hundred eighty-five thousand, six hundred fifty-two".