261431274502650 has 192 divisors, whose sum is σ = 742177899859968. Its totient is φ = 59658412450560.

The previous prime is 261431274502633. The next prime is 261431274502663. The reversal of 261431274502650 is 56205472134162.

It is a happy number.

It is a super-2 number, since 2×261431274502650² (a number of 30 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 261431274502650.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4921773892 + ... + 4921827008.

It is an arithmetic number, because the mean of its divisors is an integer number (3865509895104).

Almost surely, 2^{261431274502650} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261431274502650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (371088949929984).

261431274502650 is an abundant number, since it is smaller than the sum of its proper divisors (480746625357318).

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

261431274502650 is a wasteful number, since it uses less digits than its factorization.

261431274502650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60685 (or 60680 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 48.

The spelling of 261431274502650 in words is "two hundred sixty-one trillion, four hundred thirty-one billion, two hundred seventy-four million, five hundred two thousand, six hundred fifty".