261334921 has 4 divisors (see below), whose sum is σ = 270346500. Its totient is φ = 252323344.

The previous prime is 261334889. The next prime is 261334961. The reversal of 261334921 is 129433162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129433162 = 2 ⋅64716581.

It can be written as a sum of positive squares in 2 ways, for example, as 133079296 + 128255625 = 11536^2 + 11325^2 .

It is a cyclic number.

It is not a de Polignac number, because 261334921 - 2⁵ = 261334889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261334961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4505746 + ... + 4505803.

It is an arithmetic number, because the mean of its divisors is an integer number (67586625).

Almost surely, 2^261334921 is an apocalyptic number.

It is an amenable number.

261334921 is a deficient number, since it is larger than the sum of its proper divisors (9011579).

261334921 is an equidigital number, since it uses as much as digits as its factorization.

261334921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9011578.

The product of its digits is 7776, while the sum is 31.

The square root of 261334921 is about 16165.8566429373. The cubic root of 261334921 is about 639.3408912692.

The spelling of 261334921 in words is "two hundred sixty-one million, three hundred thirty-four thousand, nine hundred twenty-one".