261620247 has 32 divisors (see below), whose sum is σ = 407068672. Its totient is φ = 146375424.

The previous prime is 261620237. The next prime is 261620251. The reversal of 261620247 is 742026162.

It is not a de Polignac number, because 261620247 - 2⁷ = 261620119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261620207) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 240138 + ... + 241224.

It is an arithmetic number, because the mean of its divisors is an integer number (12720896).

Almost surely, 2^261620247 is an apocalyptic number.

261620247 is a deficient number, since it is larger than the sum of its proper divisors (145448425).

261620247 is a wasteful number, since it uses less digits than its factorization.

261620247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1327.

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 261620247 is about 16174.6791931092. The cubic root of 261620247 is about 639.5734845377.

The spelling of 261620247 in words is "two hundred sixty-one million, six hundred twenty thousand, two hundred forty-seven".