2643974681 has 2 divisors, whose sum is σ = 2643974682. Its totient is φ = 2643974680.

The previous prime is 2643974639. The next prime is 2643974693. The reversal of 2643974681 is 1864793462.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2092147600 + 551827081 = 45740^2 + 23491^2 .

It is a cyclic number.

It is not a de Polignac number, because 2643974681 - 2¹⁸ = 2643712537 is a prime.

It is a super-2 number, since 2×2643974681² = 13981204227538103522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2643974581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321987340 + 1321987341.

It is an arithmetic number, because the mean of its divisors is an integer number (1321987341).

Almost surely, 2^2643974681 is an apocalyptic number.

It is an amenable number.

2643974681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2643974681 is an equidigital number, since it uses as much as digits as its factorization.

2643974681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 50.

The square root of 2643974681 is about 51419.5943293994. The cubic root of 2643974681 is about 1382.7779024455. Note that the first 3 decimals are identical.

The spelling of 2643974681 in words is "two billion, six hundred forty-three million, nine hundred seventy-four thousand, six hundred eighty-one".