261449399840 has 96 divisors (see below), whose sum is σ = 629734512960. Its totient is φ = 102546791424.

The previous prime is 261449399791. The next prime is 261449399881. The reversal of 261449399840 is 48993944162.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is a self number, because there is not a number n which added to its sum of digits gives 261449399840.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3712799 + ... + 3782561.

It is an arithmetic number, because the mean of its divisors is an integer number (6559734510).

Almost surely, 2^261449399840 is an apocalyptic number.

261449399840 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 261449399840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (314867256480).

261449399840 is an abundant number, since it is smaller than the sum of its proper divisors (368285113120).

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

261449399840 is a wasteful number, since it uses less digits than its factorization.

261449399840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70234 (or 70226 counting only the distinct ones).

The product of its (nonzero) digits is 13436928, while the sum is 59.

The spelling of 261449399840 in words is "two hundred sixty-one billion, four hundred forty-nine million, three hundred ninety-nine thousand, eight hundred forty".