261051 has 16 divisors (see below), whose sum is σ = 411648. Its totient is φ = 144000.

The previous prime is 261043. The next prime is 261059. The reversal of 261051 is 150162.

261051 = 10⁵ + 11⁵.

It is an interprime number because it is at equal distance from previous prime (261043) and next prime (261059).

It is not a de Polignac number, because 261051 - 2³ = 261043 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 261051.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261051.

It is not an unprimeable number, because it can be changed into a prime (261059) 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, 451 + ... + 851.

It is an arithmetic number, because the mean of its divisors is an integer number (25728).

2²⁶¹⁰⁵¹ is an apocalyptic number.

261051 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261051 is a deficient number, since it is larger than the sum of its proper divisors (150597).

261051 is a wasteful number, since it uses less digits than its factorization.

261051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 261051 is about 510.9315022584. The cubic root of 261051 is about 63.9109275225.

Subtracting from 261051 its reverse (150162), we obtain a square (110889 = 333²).

It can be divided in two parts, 26105 and 1, that added together give a triangular number (26106 = T₂₂₈).

The spelling of 261051 in words is "two hundred sixty-one thousand, fifty-one".