261569490 has 64 divisors (see below), whose sum is σ = 772644096. Its totient is φ = 55187712.

The previous prime is 261569489. The next prime is 261569491. The reversal of 261569490 is 94965162.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (261569489) and next prime (261569491).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (261569491) 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, 45177 + ... + 50636.

It is an arithmetic number, because the mean of its divisors is an integer number (12072564).

Almost surely, 2^261569490 is an apocalyptic number.

261569490 is an abundant number, since it is smaller than the sum of its proper divisors (511074606).

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

261569490 is a wasteful number, since it uses less digits than its factorization.

261569490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95843.

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 261569490 is about 16173.1100905175. The cubic root of 261569490 is about 639.5321205998.

The spelling of 261569490 in words is "two hundred sixty-one million, five hundred sixty-nine thousand, four hundred ninety".