21256020622603 has 4 divisors (see below), whose sum is σ = 22891099132048. Its totient is φ = 19620942113160.

The previous prime is 21256020622591. The next prime is 21256020622657. The reversal of 21256020622603 is 30622602065212.

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-21256020622603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21256020622303) 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, 817539254703 + ... + 817539254728.

It is an arithmetic number, because the mean of its divisors is an integer number (5722774783012).

Almost surely, 2^{21256020622603} is an apocalyptic number.

21256020622603 is a deficient number, since it is larger than the sum of its proper divisors (1635078509445).

21256020622603 is a wasteful number, since it uses less digits than its factorization.

21256020622603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1635078509444.

The product of its (nonzero) digits is 103680, while the sum is 37.

Adding to 21256020622603 its reverse (30622602065212), we get a palindrome (51878622687815).

The spelling of 21256020622603 in words is "twenty-one trillion, two hundred fifty-six billion, twenty million, six hundred twenty-two thousand, six hundred three".