261540642 has 32 divisors (see below), whose sum is σ = 586062144. Its totient is φ = 77112000.

The previous prime is 261540623. The next prime is 261540661. The reversal of 261540642 is 246045162.

It is an interprime number because it is at equal distance from previous prime (261540623) and next prime (261540661).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51109 + ... + 55992.

It is an arithmetic number, because the mean of its divisors is an integer number (18314442).

Almost surely, 2^261540642 is an apocalyptic number.

261540642 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

261540642 is an abundant number, since it is smaller than the sum of its proper divisors (324521502).

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

261540642 is a wasteful number, since it uses less digits than its factorization.

261540642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107154.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 261540642 is about 16172.2182151986. The cubic root of 261540642 is about 639.5086088096.

The spelling of 261540642 in words is "two hundred sixty-one million, five hundred forty thousand, six hundred forty-two".