2391761987 has 4 divisors (see below), whose sum is σ = 2396461440. Its totient is φ = 2387062536.

The previous prime is 2391761959. The next prime is 2391761989. The reversal of 2391761987 is 7891671932.

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

It is a cyclic number.

It is not a de Polignac number, because 2391761987 - 2⁶ = 2391761923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2391761989) 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, 2348963 + ... + 2349980.

It is an arithmetic number, because the mean of its divisors is an integer number (599115360).

Almost surely, 2^2391761987 is an apocalyptic number.

2391761987 is a deficient number, since it is larger than the sum of its proper divisors (4699453).

2391761987 is an equidigital number, since it uses as much as digits as its factorization.

2391761987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4699452.

The product of its digits is 1143072, while the sum is 53.

The square root of 2391761987 is about 48905.6437131749. The cubic root of 2391761987 is about 1337.3322559247.

The spelling of 2391761987 in words is "two billion, three hundred ninety-one million, seven hundred sixty-one thousand, nine hundred eighty-seven".