21213612315503 has 4 divisors (see below), whose sum is σ = 21214005308760. Its totient is φ = 21213219322248.

The previous prime is 21213612315499. The next prime is 21213612315527. The reversal of 21213612315503 is 30551321631212.

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 21213612315503 - 2² = 21213612315499 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213612317503) 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, 196415648 + ... + 196523621.

It is an arithmetic number, because the mean of its divisors is an integer number (5303501327190).

Almost surely, 2^{21213612315503} is an apocalyptic number.

21213612315503 is a deficient number, since it is larger than the sum of its proper divisors (392993257).

21213612315503 is an equidigital number, since it uses as much as digits as its factorization.

21213612315503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392993256.

The product of its (nonzero) digits is 32400, while the sum is 35.

Adding to 21213612315503 its reverse (30551321631212), we get a palindrome (51764933946715).

The spelling of 21213612315503 in words is "twenty-one trillion, two hundred thirteen billion, six hundred twelve million, three hundred fifteen thousand, five hundred three".