261497808 has 400 divisors, whose sum is σ = 952814016. Its totient is φ = 68014080.

The previous prime is 261497807. The next prime is 261497809. The reversal of 261497808 is 808794162.

261497808 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261497807) and next prime (261497809).

It is a super-2 number, since 2×261497808² = 136762207177609728, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261497807) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 3150535 + ... + 3150617.

Almost surely, 2^261497808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261497808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (476407008).

261497808 is an abundant number, since it is smaller than the sum of its proper divisors (691316208).

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

261497808 is a wasteful number, since it uses less digits than its factorization.

261497808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 261497808 is about 16170.8938528456. The cubic root of 261497808 is about 639.4736949149.

The spelling of 261497808 in words is "two hundred sixty-one million, four hundred ninety-seven thousand, eight hundred eight".