261878785980 has 288 divisors, whose sum is σ = 858901317120. Its totient is φ = 59444098560.

The previous prime is 261878785951. The next prime is 261878786009. The reversal of 261878785980 is 89587878162.

It is an interprime number because it is at equal distance from previous prime (261878785951) and next prime (261878786009).

It is a super-3 number, since 3×261878785980³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

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, 427208154 + ... + 427208766.

It is an arithmetic number, because the mean of its divisors is an integer number (2982296240).

Almost surely, 2^261878785980 is an apocalyptic number.

261878785980 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 261878785980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (429450658560).

261878785980 is an abundant number, since it is smaller than the sum of its proper divisors (597022531140).

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

261878785980 is a wasteful number, since it uses less digits than its factorization.

261878785980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1409 (or 1400 counting only the distinct ones).

The product of its (nonzero) digits is 108380160, while the sum is 69.

The spelling of 261878785980 in words is "two hundred sixty-one billion, eight hundred seventy-eight million, seven hundred eighty-five thousand, nine hundred eighty".