21351120403 has 4 divisors (see below), whose sum is σ = 22607068680. Its totient is φ = 20095172128.

The previous prime is 21351120347. The next prime is 21351120419. The reversal of 21351120403 is 30402115312.

It is a happy number.

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 21351120403 - 2⁹ = 21351119891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21351120443) 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, 627974113 + ... + 627974146.

It is an arithmetic number, because the mean of its divisors is an integer number (5651767170).

Almost surely, 2^21351120403 is an apocalyptic number.

21351120403 is a deficient number, since it is larger than the sum of its proper divisors (1255948277).

21351120403 is a wasteful number, since it uses less digits than its factorization.

21351120403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255948276.

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21351120403 its reverse (30402115312), we get a palindrome (51753235715).

The spelling of 21351120403 in words is "twenty-one billion, three hundred fifty-one million, one hundred twenty thousand, four hundred three".