261261507 has 32 divisors (see below), whose sum is σ = 388700928. Its totient is φ = 155062656.

The previous prime is 261261503. The next prime is 261261523. The reversal of 261261507 is 705162162.

It is not a de Polignac number, because 261261507 - 2² = 261261503 is a prime.

It is a super-2 number, since 2×261261507² = 136515150079822098, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261261503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138253 + ... + 140129.

It is an arithmetic number, because the mean of its divisors is an integer number (12146904).

Almost surely, 2^261261507 is an apocalyptic number.

261261507 is a deficient number, since it is larger than the sum of its proper divisors (127439421).

261261507 is a wasteful number, since it uses less digits than its factorization.

261261507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2019.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 261261507 is about 16163.5858335952. The cubic root of 261261507 is about 639.2810179493.

The spelling of 261261507 in words is "two hundred sixty-one million, two hundred sixty-one thousand, five hundred seven".