19971131 has 4 divisors (see below), whose sum is σ = 20128512. Its totient is φ = 19813752.

The previous prime is 19971101. The next prime is 19971163. The reversal of 19971131 is 13117991.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19971131 is a prime.

It is a super-2 number, since 2×19971131² = 797692146838322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19971101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78500 + ... + 78753.

It is an arithmetic number, because the mean of its divisors is an integer number (5032128).

Almost surely, 2^19971131 is an apocalyptic number.

19971131 is a deficient number, since it is larger than the sum of its proper divisors (157381).

19971131 is a wasteful number, since it uses less digits than its factorization.

19971131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157380.

The product of its digits is 1701, while the sum is 32.

The square root of 19971131 is about 4468.9071370974. The cubic root of 19971131 is about 271.3110945652.

It can be divided in two parts, 19971 and 131, that added together give a palindrome (20102).

The spelling of 19971131 in words is "nineteen million, nine hundred seventy-one thousand, one hundred thirty-one".