261501649 has 8 divisors (see below), whose sum is σ = 269660160. Its totient is φ = 253428000.

The previous prime is 261501631. The next prime is 261501707. The reversal of 261501649 is 946105162.

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

It is a cyclic number.

It is not a de Polignac number, because 261501649 - 2¹³ = 261493457 is a prime.

It is a super-2 number, since 2×261501649² = 136766224859438402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261501949) 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, 14929 + ... + 27310.

It is an arithmetic number, because the mean of its divisors is an integer number (33707520).

Almost surely, 2^261501649 is an apocalyptic number.

It is an amenable number.

261501649 is a deficient number, since it is larger than the sum of its proper divisors (8158511).

261501649 is a wasteful number, since it uses less digits than its factorization.

261501649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42431.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 261501649 is about 16171.0126151704. The cubic root of 261501649 is about 639.4768258608.

The spelling of 261501649 in words is "two hundred sixty-one million, five hundred one thousand, six hundred forty-nine".