261036449520 has 960 divisors, whose sum is σ = 1071734976000. Its totient is φ = 51908075520.

The previous prime is 261036449467. The next prime is 261036449533. The reversal of 261036449520 is 25944630162.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 558964327 + ... + 558964793.

It is an arithmetic number, because the mean of its divisors is an integer number (1116390600).

Almost surely, 2^261036449520 is an apocalyptic number.

261036449520 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 261036449520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (535867488000).

261036449520 is an abundant number, since it is smaller than the sum of its proper divisors (810698526480).

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

261036449520 is a wasteful number, since it uses less digits than its factorization.

261036449520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686 (or 673 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 42.

The spelling of 261036449520 in words is "two hundred sixty-one billion, thirty-six million, four hundred forty-nine thousand, five hundred twenty".