261285430645898 has 4 divisors (see below), whose sum is σ = 391928145968850. Its totient is φ = 130642715322948.

The previous prime is 261285430645801. The next prime is 261285430645913. The reversal of 261285430645898 is 898546034582162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 161241565836649 + 100043864809249 = 12698093^2 + 10002193^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65321357661473 + ... + 65321357661476.

Almost surely, 2^{261285430645898} is an apocalyptic number.

261285430645898 is a deficient number, since it is larger than the sum of its proper divisors (130642715322952).

261285430645898 is a wasteful number, since it uses less digits than its factorization.

261285430645898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130642715322951.

The product of its (nonzero) digits is 796262400, while the sum is 71.

The spelling of 261285430645898 in words is "two hundred sixty-one trillion, two hundred eighty-five billion, four hundred thirty million, six hundred forty-five thousand, eight hundred ninety-eight".