261021080 has 32 divisors (see below), whose sum is σ = 599797440. Its totient is φ = 102186240.

The previous prime is 261021071. The next prime is 261021091. The reversal of 261021080 is 80120162.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

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, 67541 + ... + 71300.

It is an arithmetic number, because the mean of its divisors is an integer number (18743670).

Almost surely, 2^261021080 is an apocalyptic number.

261021080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261021080 is an abundant number, since it is smaller than the sum of its proper divisors (338776360).

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

261021080 is a wasteful number, since it uses less digits than its factorization.

261021080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138899 (or 138895 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 261021080 is about 16156.1468178523. The cubic root of 261021080 is about 639.0848574165.

The spelling of 261021080 in words is "two hundred sixty-one million, twenty-one thousand, eighty".