261229540 has 96 divisors (see below), whose sum is σ = 648869760. Its totient is φ = 87091200.

The previous prime is 261229523. The next prime is 261229541. The reversal of 261229540 is 45922162.

261229540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×261229540² = 136481745137223200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261229541) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 689071 + ... + 689449.

It is an arithmetic number, because the mean of its divisors is an integer number (6759060).

Almost surely, 2^261229540 is an apocalyptic number.

261229540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261229540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (324434880).

261229540 is an abundant number, since it is smaller than the sum of its proper divisors (387640220).

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

261229540 is a wasteful number, since it uses less digits than its factorization.

261229540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 653 (or 651 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 261229540 is about 16162.5969447982. The cubic root of 261229540 is about 639.2549435254.

The spelling of 261229540 in words is "two hundred sixty-one million, two hundred twenty-nine thousand, five hundred forty".