261896438840 has 16 divisors (see below), whose sum is σ = 589266987480. Its totient is φ = 104758575520.

The previous prime is 261896438833. The next prime is 261896438849. The reversal of 261896438840 is 48834698162.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 261896438840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261896438849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3273705446 + ... + 3273705525.

Almost surely, 2^261896438840 is an apocalyptic number.

261896438840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261896438840 is an abundant number, since it is smaller than the sum of its proper divisors (327370548640).

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

261896438840 is a wasteful number, since it uses less digits than its factorization.

261896438840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6547410982 (or 6547410978 counting only the distinct ones).

The product of its (nonzero) digits is 15925248, while the sum is 59.

The spelling of 261896438840 in words is "two hundred sixty-one billion, eight hundred ninety-six million, four hundred thirty-eight thousand, eight hundred forty".