261640724 has 24 divisors (see below), whose sum is σ = 469532448. Its totient is φ = 127501920.

The previous prime is 261640723. The next prime is 261640741. The reversal of 261640724 is 427046162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261640723) 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, 94439 + ... + 97169.

It is an arithmetic number, because the mean of its divisors is an integer number (19563852).

Almost surely, 2^261640724 is an apocalyptic number.

It is an amenable number.

261640724 is a deficient number, since it is larger than the sum of its proper divisors (207891724).

261640724 is a wasteful number, since it uses less digits than its factorization.

261640724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3335 (or 3333 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 261640724 is about 16175.3121762765. The cubic root of 261640724 is about 639.5901705610.

Adding to 261640724 its reverse (427046162), we get a palindrome (688686886).

The spelling of 261640724 in words is "two hundred sixty-one million, six hundred forty thousand, seven hundred twenty-four".