2971731981 has 4 divisors (see below), whose sum is σ = 3962309312. Its totient is φ = 1981154652.

The previous prime is 2971731979. The next prime is 2971731991. The reversal of 2971731981 is 1891371792.

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 not a de Polignac number, because 2971731981 - 2¹ = 2971731979 is a prime.

It is a super-2 number, since 2×2971731981² = 17662381933796368722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2971731981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2971731911) 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, 495288661 + ... + 495288666.

It is an arithmetic number, because the mean of its divisors is an integer number (990577328).

Almost surely, 2^2971731981 is an apocalyptic number.

It is an amenable number.

2971731981 is a deficient number, since it is larger than the sum of its proper divisors (990577331).

2971731981 is an equidigital number, since it uses as much as digits as its factorization.

2971731981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 990577330.

The product of its digits is 190512, while the sum is 48.

The square root of 2971731981 is about 54513.5944604646. The cubic root of 2971731981 is about 1437.7053185847.

The spelling of 2971731981 in words is "two billion, nine hundred seventy-one million, seven hundred thirty-one thousand, nine hundred eighty-one".