21521002403 has 8 divisors (see below), whose sum is σ = 22737285120. Its totient is φ = 20313079560.

The previous prime is 21521002367. The next prime is 21521002409. The reversal of 21521002403 is 30420012512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21521002403 - 2⁸ = 21521002147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21521002409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2084675 + ... + 2094972.

It is an arithmetic number, because the mean of its divisors is an integer number (2842160640).

Almost surely, 2^21521002403 is an apocalyptic number.

21521002403 is a deficient number, since it is larger than the sum of its proper divisors (1216282717).

21521002403 is a wasteful number, since it uses less digits than its factorization.

21521002403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4179937.

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 21521002403 its reverse (30420012512), we get a palindrome (51941014915).

The spelling of 21521002403 in words is "twenty-one billion, five hundred twenty-one million, two thousand, four hundred three".