261558100 has 18 divisors (see below), whose sum is σ = 567581294. Its totient is φ = 104623200.

The previous prime is 261558083. The next prime is 261558103. The reversal of 261558100 is 1855162.

It can be written as a sum of positive squares in 3 ways, for example, as 20811844 + 240746256 = 4562^2 + 15516^2 .

It is a super-2 number, since 2×261558100² = 136825279351220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261558103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1307691 + ... + 1307890.

Almost surely, 2^261558100 is an apocalyptic number.

261558100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261558100 is an abundant number, since it is smaller than the sum of its proper divisors (306023194).

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

261558100 is a wasteful number, since it uses less digits than its factorization.

261558100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2615595 (or 2615588 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 261558100 is about 16172.7579589877. The cubic root of 261558100 is about 639.5228376917.

The spelling of 261558100 in words is "two hundred sixty-one million, five hundred fifty-eight thousand, one hundred".