261222739 has 2 divisors, whose sum is σ = 261222740. Its totient is φ = 261222738.

The previous prime is 261222733. The next prime is 261222761. The reversal of 261222739 is 937222162.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261222739 - 2²⁵ = 227668307 is a prime.

It is not a weakly prime, because it can be changed into another prime (261222733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130611369 + 130611370.

It is an arithmetic number, because the mean of its divisors is an integer number (130611370).

Almost surely, 2^261222739 is an apocalyptic number.

261222739 is a deficient number, since it is larger than the sum of its proper divisors (1).

261222739 is an equidigital number, since it uses as much as digits as its factorization.

261222739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 34.

The square root of 261222739 is about 16162.3865502592. The cubic root of 261222739 is about 639.2493959004.

The spelling of 261222739 in words is "two hundred sixty-one million, two hundred twenty-two thousand, seven hundred thirty-nine".