203878865428121 has 4 divisors (see below), whose sum is σ = 219561855076452. Its totient is φ = 188195875779792.

The previous prime is 203878865428019. The next prime is 203878865428193. The reversal of 203878865428121 is 121824568878302.

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

It can be written as a sum of positive squares in 2 ways, for example, as 27747188353600 + 176131677074521 = 5267560^2 + 13271461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-203878865428121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (203878865427121) 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, 7841494824146 + ... + 7841494824171.

It is an arithmetic number, because the mean of its divisors is an integer number (54890463769113).

Almost surely, 2^{203878865428121} is an apocalyptic number.

It is an amenable number.

203878865428121 is a deficient number, since it is larger than the sum of its proper divisors (15682989648331).

203878865428121 is a wasteful number, since it uses less digits than its factorization.

203878865428121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15682989648330.

The product of its (nonzero) digits is 82575360, while the sum is 65.

The spelling of 203878865428121 in words is "two hundred three trillion, eight hundred seventy-eight billion, eight hundred sixty-five million, four hundred twenty-eight thousand, one hundred twenty-one".