261939770247 has 8 divisors (see below), whose sum is σ = 356683942656. Its totient is φ = 170911055672.

The previous prime is 261939770221. The next prime is 261939770273. The reversal of 261939770247 is 742077939162.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (261939770221) and next prime (261939770273).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261939770247 - 2¹⁶ = 261939704711 is a prime.

It is a super-2 number, since 2×261939770247² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261939770207) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 928864293 + ... + 928864574.

It is an arithmetic number, because the mean of its divisors is an integer number (44585492832).

Almost surely, 2^261939770247 is an apocalyptic number.

261939770247 is a deficient number, since it is larger than the sum of its proper divisors (94744172409).

261939770247 is a wasteful number, since it uses less digits than its factorization.

261939770247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1857728917.

The product of its (nonzero) digits is 8001504, while the sum is 57.

The spelling of 261939770247 in words is "two hundred sixty-one billion, nine hundred thirty-nine million, seven hundred seventy thousand, two hundred forty-seven".