261249867 has 20 divisors (see below), whose sum is σ = 410804680. Its totient is φ = 164998944.

The previous prime is 261249853. The next prime is 261249869. The reversal of 261249867 is 768942162.

It is a happy number.

It is not a de Polignac number, because 261249867 - 2¹² = 261245771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261249869) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 83338 + ... + 86415.

It is an arithmetic number, because the mean of its divisors is an integer number (20540234).

Almost surely, 2^261249867 is an apocalyptic number.

261249867 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

261249867 is a deficient number, since it is larger than the sum of its proper divisors (149554813).

261249867 is a wasteful number, since it uses less digits than its factorization.

261249867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169784 (or 169775 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 261249867 is about 16163.2257609674. The cubic root of 261249867 is about 639.2715238328.

The spelling of 261249867 in words is "two hundred sixty-one million, two hundred forty-nine thousand, eight hundred sixty-seven".