261819648 has 72 divisors (see below), whose sum is σ = 774267200. Its totient is φ = 87270912.

The previous prime is 261819641. The next prime is 261819661. The reversal of 261819648 is 846918162.

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261819641) 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, 12028 + ... + 25851.

Almost surely, 2^261819648 is an apocalyptic number.

It is an amenable number.

261819648 is an abundant number, since it is smaller than the sum of its proper divisors (512447552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261819648 is an equidigital number, since it uses as much as digits as its factorization.

261819648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37904 (or 37884 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 261819648 is about 16180.8420052851. The cubic root of 261819648 is about 639.7359327261.

The spelling of 261819648 in words is "two hundred sixty-one million, eight hundred nineteen thousand, six hundred forty-eight".