261440739 has 24 divisors (see below), whose sum is σ = 456973920. Its totient is φ = 140606208.

The previous prime is 261440689. The next prime is 261440801. The reversal of 261440739 is 937044162.

261440739 is a `hidden beast` number, since 2 + 614 + 4 + 0 + 7 + 39 = 666.

It is not a de Polignac number, because 261440739 - 2¹¹ = 261438691 is a prime.

It is a super-2 number, since 2×261440739² = 136702520017732242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261440939) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120984 + ... + 123125.

It is an arithmetic number, because the mean of its divisors is an integer number (19040580).

Almost surely, 2^261440739 is an apocalyptic number.

261440739 is a deficient number, since it is larger than the sum of its proper divisors (195533181).

261440739 is a wasteful number, since it uses less digits than its factorization.

261440739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244139 (or 244136 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 261440739 is about 16169.1291973316. The cubic root of 261440739 is about 639.4271721802.

The spelling of 261440739 in words is "two hundred sixty-one million, four hundred forty thousand, seven hundred thirty-nine".