261605662537 has 8 divisors (see below), whose sum is σ = 262472027904. Its totient is φ = 260740722768.

The previous prime is 261605662517. The next prime is 261605662547. The reversal of 261605662537 is 735266506162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261605662537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261605662517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11848 + ... + 723430.

It is an arithmetic number, because the mean of its divisors is an integer number (32809003488).

Almost surely, 2^261605662537 is an apocalyptic number.

It is an amenable number.

261605662537 is a deficient number, since it is larger than the sum of its proper divisors (866365367).

261605662537 is an equidigital number, since it uses as much as digits as its factorization.

261605662537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712799.

The product of its (nonzero) digits is 2721600, while the sum is 49.

The spelling of 261605662537 in words is "two hundred sixty-one billion, six hundred five million, six hundred sixty-two thousand, five hundred thirty-seven".