261243634 has 16 divisors (see below), whose sum is σ = 404997120. Its totient is φ = 126254880.

The previous prime is 261243623. The next prime is 261243649. The reversal of 261243634 is 436342162.

261243634 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 261243596 and 261243605.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62007 + ... + 66085.

It is an arithmetic number, because the mean of its divisors is an integer number (25312320).

Almost surely, 2^261243634 is an apocalyptic number.

261243634 is a deficient number, since it is larger than the sum of its proper divisors (143753486).

261243634 is a wasteful number, since it uses less digits than its factorization.

261243634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5145.

The product of its digits is 20736, while the sum is 31.

The square root of 261243634 is about 16163.0329455830. The cubic root of 261243634 is about 639.2664397969.

Adding to 261243634 its reverse (436342162), we get a palindrome (697585796).

The spelling of 261243634 in words is "two hundred sixty-one million, two hundred forty-three thousand, six hundred thirty-four".