21278857873403 has 4 divisors (see below), whose sum is σ = 22915693094448. Its totient is φ = 19642022652360.

The previous prime is 21278857873397. The next prime is 21278857873477. The reversal of 21278857873403 is 30437875887212.

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

It is a cyclic number.

It is not a de Polignac number, because 21278857873403 - 2²⁴ = 21278841096187 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21278857873403.

It is not an unprimeable number, because it can be changed into a prime (21278857876403) 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, 818417610503 + ... + 818417610528.

It is an arithmetic number, because the mean of its divisors is an integer number (5728923273612).

Almost surely, 2^{21278857873403} is an apocalyptic number.

21278857873403 is a deficient number, since it is larger than the sum of its proper divisors (1636835221045).

21278857873403 is a wasteful number, since it uses less digits than its factorization.

21278857873403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636835221044.

The product of its (nonzero) digits is 126443520, while the sum is 65.

The spelling of 21278857873403 in words is "twenty-one trillion, two hundred seventy-eight billion, eight hundred fifty-seven million, eight hundred seventy-three thousand, four hundred three".