261148403640 has 128 divisors (see below), whose sum is σ = 787176532800. Its totient is φ = 69308559360.

The previous prime is 261148403629. The next prime is 261148403657. The reversal of 261148403640 is 46304841162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28439850 + ... + 28449030.

Almost surely, 2^261148403640 is an apocalyptic number.

261148403640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261148403640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393588266400).

261148403640 is an abundant number, since it is smaller than the sum of its proper divisors (526028129160).

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

261148403640 is a wasteful number, since it uses less digits than its factorization.

261148403640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10297 (or 10293 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 39.

The spelling of 261148403640 in words is "two hundred sixty-one billion, one hundred forty-eight million, four hundred three thousand, six hundred forty".