261940890 has 16 divisors (see below), whose sum is σ = 628658208. Its totient is φ = 69850896.

The previous prime is 261940867. The next prime is 261940891. The reversal of 261940890 is 98049162.

It is a super-2 number, since 2×261940890² = 137226059707984200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261940891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4365652 + ... + 4365711.

It is an arithmetic number, because the mean of its divisors is an integer number (39291138).

Almost surely, 2^261940890 is an apocalyptic number.

261940890 is an abundant number, since it is smaller than the sum of its proper divisors (366717318).

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

261940890 is a wasteful number, since it uses less digits than its factorization.

261940890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8731373.

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 261940890 is about 16184.5880392428. The cubic root of 261940890 is about 639.8346659511.

The spelling of 261940890 in words is "two hundred sixty-one million, nine hundred forty thousand, eight hundred ninety".