261187820 has 12 divisors (see below), whose sum is σ = 548494464. Its totient is φ = 104475120.

The previous prime is 261187807. The next prime is 261187831. The reversal of 261187820 is 28781162.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6529676 + ... + 6529715.

It is an arithmetic number, because the mean of its divisors is an integer number (45707872).

Almost surely, 2^261187820 is an apocalyptic number.

261187820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261187820 is an abundant number, since it is smaller than the sum of its proper divisors (287306644).

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

261187820 is a wasteful number, since it uses less digits than its factorization.

261187820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13059400 (or 13059398 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 261187820 is about 16161.3062590869. The cubic root of 261187820 is about 639.2209107023.

The spelling of 261187820 in words is "two hundred sixty-one million, one hundred eighty-seven thousand, eight hundred twenty".