261572198399 has 4 divisors (see below), whose sum is σ = 261786077136. Its totient is φ = 261358319664.

The previous prime is 261572198389. The next prime is 261572198431. The reversal of 261572198399 is 993891275162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261572198399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261572198389) 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, 106937534 + ... + 106939979.

It is an arithmetic number, because the mean of its divisors is an integer number (65446519284).

Almost surely, 2^261572198399 is an apocalyptic number.

261572198399 is a deficient number, since it is larger than the sum of its proper divisors (213878737).

261572198399 is a wasteful number, since it uses less digits than its factorization.

261572198399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213878736.

The product of its digits is 14696640, while the sum is 62.

The spelling of 261572198399 in words is "two hundred sixty-one billion, five hundred seventy-two million, one hundred ninety-eight thousand, three hundred ninety-nine".