261555428 has 12 divisors (see below), whose sum is σ = 457855020. Its totient is φ = 130739712.

The previous prime is 261555403. The next prime is 261555449. The reversal of 261555428 is 824555162.

261555428 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 10903204 + 250652224 = 3302^2 + 15832^2 .

It is a super-2 number, since 2×261555428² = 136822483832526368, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261555391 and 261555400.

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, 10808 + ... + 25296.

It is an arithmetic number, because the mean of its divisors is an integer number (38154585).

Almost surely, 2^261555428 is an apocalyptic number.

It is an amenable number.

261555428 is a deficient number, since it is larger than the sum of its proper divisors (196299592).

261555428 is a wasteful number, since it uses less digits than its factorization.

261555428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19006 (or 19004 counting only the distinct ones).

The product of its digits is 96000, while the sum is 38.

The square root of 261555428 is about 16172.6753507266. The cubic root of 261555428 is about 639.5206599591.

The spelling of 261555428 in words is "two hundred sixty-one million, five hundred fifty-five thousand, four hundred twenty-eight".