261421911 has 10 divisors (see below), whose sum is σ = 390519272. Its totient is φ = 174281220.

The previous prime is 261421883. The next prime is 261421957. The reversal of 261421911 is 119124162.

It is not a de Polignac number, because 261421911 - 2¹⁷ = 261290839 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261421961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1613635 + ... + 1613796.

Almost surely, 2^261421911 is an apocalyptic number.

261421911 is a deficient number, since it is larger than the sum of its proper divisors (129097361).

261421911 is an equidigital number, since it uses as much as digits as its factorization.

261421911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3227443 (or 3227434 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 261421911 is about 16168.5469662552. The cubic root of 261421911 is about 639.4118220811.

The spelling of 261421911 in words is "two hundred sixty-one million, four hundred twenty-one thousand, nine hundred eleven".