2194637581 has 2 divisors, whose sum is σ = 2194637582. Its totient is φ = 2194637580.

The previous prime is 2194637567. The next prime is 2194637603. The reversal of 2194637581 is 1857364912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2024100100 + 170537481 = 44990^2 + 13059^2 .

It is a cyclic number.

It is not a de Polignac number, because 2194637581 - 2²¹ = 2192540429 is a prime.

It is a super-2 number, since 2×2194637581² = 9632868223875063122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2194137581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1097318790 + 1097318791.

It is an arithmetic number, because the mean of its divisors is an integer number (1097318791).

Almost surely, 2^2194637581 is an apocalyptic number.

It is an amenable number.

2194637581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2194637581 is an equidigital number, since it uses as much as digits as its factorization.

2194637581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 46.

The square root of 2194637581 is about 46846.9591435773. The cubic root of 2194637581 is about 1299.5338725305.

The spelling of 2194637581 in words is "two billion, one hundred ninety-four million, six hundred thirty-seven thousand, five hundred eighty-one".