261784534 has 16 divisors (see below), whose sum is σ = 435637440. Its totient is φ = 116975560.

The previous prime is 261784531. The next prime is 261784571. The reversal of 261784534 is 435487162.

It is a super-2 number, since 2×261784534² = 137062284483194312, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261784531) 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, 99544 + ... + 102139.

It is an arithmetic number, because the mean of its divisors is an integer number (27227340).

Almost surely, 2^261784534 is an apocalyptic number.

261784534 is a deficient number, since it is larger than the sum of its proper divisors (173852906).

261784534 is a wasteful number, since it uses less digits than its factorization.

261784534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201755.

The product of its digits is 161280, while the sum is 40.

The square root of 261784534 is about 16179.7569203001. The cubic root of 261784534 is about 639.7073320055.

The spelling of 261784534 in words is "two hundred sixty-one million, seven hundred eighty-four thousand, five hundred thirty-four".