261022216500 has 576 divisors, whose sum is σ = 905789294592. Its totient is φ = 65505024000.

The previous prime is 261022216487. The next prime is 261022216517. The reversal of 261022216500 is 5612220162.

261022216500 is a `hidden beast` number, since 2 + 6 + 1 + 0 + 2 + 2 + 2 + 1 + 650 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 139359564 + ... + 139361436.

Almost surely, 2^261022216500 is an apocalyptic number.

261022216500 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 261022216500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (452894647296).

261022216500 is an abundant number, since it is smaller than the sum of its proper divisors (644767078092).

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

261022216500 is a wasteful number, since it uses less digits than its factorization.

261022216500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1975 (or 1951 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 261022216500 its reverse (5612220162), we get a palindrome (266634436662).

The spelling of 261022216500 in words is "two hundred sixty-one billion, twenty-two million, two hundred sixteen thousand, five hundred".