261621761 has 8 divisors (see below), whose sum is σ = 267969504. Its totient is φ = 255286080.

The previous prime is 261621749. The next prime is 261621793. The reversal of 261621761 is 167126162.

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 261621761 - 2¹⁸ = 261359617 is a prime.

It is a super-2 number, since 2×261621761² = 136891891657482242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261621161) 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, 53426 + ... + 58116.

It is an arithmetic number, because the mean of its divisors is an integer number (33496188).

Almost surely, 2^261621761 is an apocalyptic number.

It is an amenable number.

261621761 is a deficient number, since it is larger than the sum of its proper divisors (6347743).

261621761 is a wasteful number, since it uses less digits than its factorization.

261621761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6031.

The product of its digits is 6048, while the sum is 32.

The square root of 261621761 is about 16174.7259945880. The cubic root of 261621761 is about 639.5747182755.

The spelling of 261621761 in words is "two hundred sixty-one million, six hundred twenty-one thousand, seven hundred sixty-one".