261815143 has 2 divisors, whose sum is σ = 261815144. Its totient is φ = 261815142.

The previous prime is 261815123. The next prime is 261815153. The reversal of 261815143 is 341518162.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261815143 is a prime.

It is a super-2 number, since 2×261815143² = 137094338208220898, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261815123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130907571 + 130907572.

It is an arithmetic number, because the mean of its divisors is an integer number (130907572).

Almost surely, 2^261815143 is an apocalyptic number.

261815143 is a deficient number, since it is larger than the sum of its proper divisors (1).

261815143 is an equidigital number, since it uses as much as digits as its factorization.

261815143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 31.

The square root of 261815143 is about 16180.7027968503. The cubic root of 261815143 is about 639.7322634995.

The spelling of 261815143 in words is "two hundred sixty-one million, eight hundred fifteen thousand, one hundred forty-three".