2187931997 has 4 divisors (see below), whose sum is σ = 2205159936. Its totient is φ = 2170704060.

The previous prime is 2187931973. The next prime is 2187932029. The reversal of 2187931997 is 7991397812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2187931997 - 2²⁸ = 1919496541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2187931937) 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, 8613779 + ... + 8614032.

It is an arithmetic number, because the mean of its divisors is an integer number (551289984).

Almost surely, 2^2187931997 is an apocalyptic number.

It is an amenable number.

2187931997 is a deficient number, since it is larger than the sum of its proper divisors (17227939).

2187931997 is a wasteful number, since it uses less digits than its factorization.

2187931997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17227938.

The product of its digits is 1714608, while the sum is 56.

The square root of 2187931997 is about 46775.3353488780. The cubic root of 2187931997 is about 1298.2089728620.

The spelling of 2187931997 in words is "two billion, one hundred eighty-seven million, nine hundred thirty-one thousand, nine hundred ninety-seven".