19947890169 has 21 divisors (see below), whose sum is σ = 29913872149. Its totient is φ = 13296051180.

The previous prime is 19947890089. The next prime is 19947890177. The reversal of 19947890169 is 96109874991.

The square root of 19947890169 is 141237.

It is a perfect power (a square), and thus also a powerful number.

19947890169 is a `hidden beast` number, since 19 + 9 + 478 + 90 + 1 + 69 = 666.

It is not a de Polignac number, because 19947890169 - 2⁹ = 19947889657 is a prime.

It is a super-2 number, since 2×19947890169² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19947895169) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 3810784 + ... + 3816014.

Almost surely, 2^19947890169 is an apocalyptic number.

19947890169 is the 141237-th square number.

19947890169 is the 70619-th centered octagonal number.

It is an amenable number.

19947890169 is a deficient number, since it is larger than the sum of its proper divisors (9965981980).

19947890169 is an frugal number, since it uses more digits than its factorization.

19947890169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10480 (or 5234 counting only the distinct ones).

The product of its (nonzero) digits is 8817984, while the sum is 63.

It can be divided in two parts, 19947 and 890169, that added together give a square (910116 = 954²).

The spelling of 19947890169 in words is "nineteen billion, nine hundred forty-seven million, eight hundred ninety thousand, one hundred sixty-nine".