2118747681 has 6 divisors (see below), whose sum is σ = 3060413330. Its totient is φ = 1412498448.

The previous prime is 2118747677. The next prime is 2118747691. The reversal of 2118747681 is 1867478112.

2118747681 is a `hidden beast` number, since 21 + 1 + 87 + 476 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2077992225 + 40755456 = 45585^2 + 6384^2 .

It is not a de Polignac number, because 2118747681 - 2² = 2118747677 is a prime.

It is a super-2 number, since 2×2118747681² = 8978183471485755522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2118747601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 117708196 + ... + 117708213.

Almost surely, 2^2118747681 is an apocalyptic number.

It is an amenable number.

2118747681 is a deficient number, since it is larger than the sum of its proper divisors (941665649).

2118747681 is a wasteful number, since it uses less digits than its factorization.

2118747681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235416415 (or 235416412 counting only the distinct ones).

The product of its digits is 150528, while the sum is 45.

The square root of 2118747681 is about 46029.8564086398. The cubic root of 2118747681 is about 1284.3786568458.

The spelling of 2118747681 in words is "two billion, one hundred eighteen million, seven hundred forty-seven thousand, six hundred eighty-one".