261700665 has 32 divisors (see below), whose sum is σ = 426577536. Its totient is φ = 136980480.

The previous prime is 261700657. The next prime is 261700723. The reversal of 261700665 is 566007162.

It is not a de Polignac number, because 261700665 - 2³ = 261700657 is a prime.

It is a super-2 number, since 2×261700665² = 136974476122884450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 189919 + ... + 191291.

It is an arithmetic number, because the mean of its divisors is an integer number (13330548).

Almost surely, 2^261700665 is an apocalyptic number.

It is an amenable number.

261700665 is a deficient number, since it is larger than the sum of its proper divisors (164876871).

261700665 is a wasteful number, since it uses less digits than its factorization.

261700665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1609.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 261700665 is about 16177.1649246708. The cubic root of 261700665 is about 639.6390094758.

The spelling of 261700665 in words is "two hundred sixty-one million, seven hundred thousand, six hundred sixty-five".