261311960 has 64 divisors (see below), whose sum is σ = 723643200. Its totient is φ = 82699776.

The previous prime is 261311957. The next prime is 261311969. The reversal of 261311960 is 69113162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261311969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32255 + ... + 39534.

It is an arithmetic number, because the mean of its divisors is an integer number (11306925).

Almost surely, 2^261311960 is an apocalyptic number.

261311960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261311960 is an abundant number, since it is smaller than the sum of its proper divisors (462331240).

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

261311960 is a wasteful number, since it uses less digits than its factorization.

261311960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71820 (or 71816 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 261311960 is about 16165.1464577343. The cubic root of 261311960 is about 639.3221664644.

The spelling of 261311960 in words is "two hundred sixty-one million, three hundred eleven thousand, nine hundred sixty".