261965668 has 24 divisors (see below), whose sum is σ = 465454080. Its totient is φ = 128993280.

The previous prime is 261965657. The next prime is 261965689. The reversal of 261965668 is 866569162.

It is a happy number.

It is a super-2 number, since 2×261965668² = 137252022421372448, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77028 + ... + 80356.

It is an arithmetic number, because the mean of its divisors is an integer number (19393920).

Almost surely, 2^261965668 is an apocalyptic number.

It is an amenable number.

261965668 is a deficient number, since it is larger than the sum of its proper divisors (203488412).

261965668 is a wasteful number, since it uses less digits than its factorization.

261965668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3627 (or 3625 counting only the distinct ones).

The product of its digits is 933120, while the sum is 49.

The square root of 261965668 is about 16185.3535024725. The cubic root of 261965668 is about 639.8548401253.

The spelling of 261965668 in words is "two hundred sixty-one million, nine hundred sixty-five thousand, six hundred sixty-eight".