19977353197 has 4 divisors (see below), whose sum is σ = 20464605756. Its totient is φ = 19490100640.

The previous prime is 19977353183. The next prime is 19977353203. The reversal of 19977353197 is 79135377991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11248935721 + 8728417476 = 106061^2 + 93426^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19977353197 is a prime.

It is a super-2 number, since 2×19977353197² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19977353117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243626218 + ... + 243626299.

It is an arithmetic number, because the mean of its divisors is an integer number (5116151439).

Almost surely, 2^19977353197 is an apocalyptic number.

It is an amenable number.

19977353197 is a deficient number, since it is larger than the sum of its proper divisors (487252559).

19977353197 is an equidigital number, since it uses as much as digits as its factorization.

19977353197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487252558.

The product of its digits is 11252115, while the sum is 61.

The spelling of 19977353197 in words is "nineteen billion, nine hundred seventy-seven million, three hundred fifty-three thousand, one hundred ninety-seven".