261660615 has 16 divisors (see below), whose sum is σ = 432162816. Its totient is φ = 135050400.

The previous prime is 261660611. The next prime is 261660643. The reversal of 261660615 is 516066162.

It is not a de Polignac number, because 261660615 - 2² = 261660611 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261660611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 280891 + ... + 281820.

It is an arithmetic number, because the mean of its divisors is an integer number (27010176).

Almost surely, 2^261660615 is an apocalyptic number.

261660615 is a deficient number, since it is larger than the sum of its proper divisors (170502201).

261660615 is a wasteful number, since it uses less digits than its factorization.

261660615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562750.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 261660615 is about 16175.9270213487. The cubic root of 261660615 is about 639.6063782388.

The spelling of 261660615 in words is "two hundred sixty-one million, six hundred sixty thousand, six hundred fifteen".