261861372 has 18 divisors (see below), whose sum is σ = 661927448. Its totient is φ = 87287112.

The previous prime is 261861367. The next prime is 261861403. The reversal of 261861372 is 273168162.

261861372 is a `hidden beast` number, since 2 + 618 + 6 + 1 + 37 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 7273927 = 261861372 / (2 + 6 + 1 + 8 + 6 + 1 + 3 + 7 + 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3636928 + ... + 3636999.

Almost surely, 2^261861372 is an apocalyptic number.

It is an amenable number.

261861372 is an abundant number, since it is smaller than the sum of its proper divisors (400066076).

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

261861372 is a wasteful number, since it uses less digits than its factorization.

261861372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7273937 (or 7273932 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 261861372 is about 16182.1312564198. The cubic root of 261861372 is about 639.7699140367.

The spelling of 261861372 in words is "two hundred sixty-one million, eight hundred sixty-one thousand, three hundred seventy-two".