21523454403 has 16 divisors (see below), whose sum is σ = 31312434816. Its totient is φ = 13042187840.

The previous prime is 21523454399. The next prime is 21523454461. The reversal of 21523454403 is 30445432512.

It is not a de Polignac number, because 21523454403 - 2² = 21523454399 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21523454483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139300 + ... + 249902.

It is an arithmetic number, because the mean of its divisors is an integer number (1957027176).

Almost surely, 2^21523454403 is an apocalyptic number.

21523454403 is a deficient number, since it is larger than the sum of its proper divisors (9788980413).

21523454403 is a wasteful number, since it uses less digits than its factorization.

21523454403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116514.

The product of its (nonzero) digits is 57600, while the sum is 33.

Adding to 21523454403 its reverse (30445432512), we get a palindrome (51968886915).

The spelling of 21523454403 in words is "twenty-one billion, five hundred twenty-three million, four hundred fifty-four thousand, four hundred three".