261511770 has 32 divisors (see below), whose sum is σ = 675908352. Its totient is φ = 64372032.

The previous prime is 261511759. The next prime is 261511781. The reversal of 261511770 is 77115162.

It is an interprime number because it is at equal distance from previous prime (261511759) and next prime (261511781).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 334882 + ... + 335661.

It is an arithmetic number, because the mean of its divisors is an integer number (21122136).

Almost surely, 2^261511770 is an apocalyptic number.

261511770 is an abundant number, since it is smaller than the sum of its proper divisors (414396582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261511770 is a wasteful number, since it uses less digits than its factorization.

261511770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 670566.

The product of its (nonzero) digits is 2940, while the sum is 30.

The square root of 261511770 is about 16171.3255486370. The cubic root of 261511770 is about 639.4850757278.

The spelling of 261511770 in words is "two hundred sixty-one million, five hundred eleven thousand, seven hundred seventy".