261215154 has 24 divisors (see below), whose sum is σ = 595754640. Its totient is φ = 82488888.

The previous prime is 261215131. The next prime is 261215167. The reversal of 261215154 is 451512162.

261215154 is a `hidden beast` number, since 26 + 121 + 515 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 381552 + ... + 382235.

It is an arithmetic number, because the mean of its divisors is an integer number (24823110).

Almost surely, 2^261215154 is an apocalyptic number.

261215154 is an abundant number, since it is smaller than the sum of its proper divisors (334539486).

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

261215154 is a wasteful number, since it uses less digits than its factorization.

261215154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763814 (or 763811 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 261215154 is about 16162.1518988036. The cubic root of 261215154 is about 639.2432086473.

It can be divided in two parts, 2612 and 15154, that added together give a triangular number (17766 = T₁₈₈).

The spelling of 261215154 in words is "two hundred sixty-one million, two hundred fifteen thousand, one hundred fifty-four".