261157990 has 16 divisors (see below), whose sum is σ = 471050640. Its totient is φ = 104248480.

The previous prime is 261157979. The next prime is 261157999. The reversal of 261157990 is 99751162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261157999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21685 + ... + 31504.

It is an arithmetic number, because the mean of its divisors is an integer number (29440665).

Almost surely, 2^261157990 is an apocalyptic number.

261157990 is a deficient number, since it is larger than the sum of its proper divisors (209892650).

261157990 is a wasteful number, since it uses less digits than its factorization.

261157990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53687.

The product of its (nonzero) digits is 34020, while the sum is 40.

The square root of 261157990 is about 16160.3833494135. The cubic root of 261157990 is about 639.1965748486.

The spelling of 261157990 in words is "two hundred sixty-one million, one hundred fifty-seven thousand, nine hundred ninety".