261431101 has 2 divisors, whose sum is σ = 261431102. Its totient is φ = 261431100.

The previous prime is 261431077. The next prime is 261431123. The reversal of 261431101 is 101134162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203747076 + 57684025 = 14274^2 + 7595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261431101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261431141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130715550 + 130715551.

It is an arithmetic number, because the mean of its divisors is an integer number (130715551).

Almost surely, 2^261431101 is an apocalyptic number.

It is an amenable number.

261431101 is a deficient number, since it is larger than the sum of its proper divisors (1).

261431101 is an equidigital number, since it uses as much as digits as its factorization.

261431101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 261431101 is about 16168.8311575080. The cubic root of 261431101 is about 639.4193145999.

Adding to 261431101 its reverse (101134162), we get a palindrome (362565263).

The spelling of 261431101 in words is "two hundred sixty-one million, four hundred thirty-one thousand, one hundred one".