261660538 has 8 divisors (see below), whose sum is σ = 392753088. Its totient is φ = 130742844.

The previous prime is 261660521. The next prime is 261660551. The reversal of 261660538 is 835066162.

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

It is a junction number, because it is equal to n+sod(n) for n = 261660497 and 261660506.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39906 + ... + 45997.

It is an arithmetic number, because the mean of its divisors is an integer number (49094136).

Almost surely, 2^261660538 is an apocalyptic number.

261660538 is a deficient number, since it is larger than the sum of its proper divisors (131092550).

261660538 is a wasteful number, since it uses less digits than its factorization.

261660538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87428.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 261660538 is about 16175.9246412686. The cubic root of 261660538 is about 639.6063154989.

The spelling of 261660538 in words is "two hundred sixty-one million, six hundred sixty thousand, five hundred thirty-eight".