21315155363 has 4 divisors (see below), whose sum is σ = 21482991360. Its totient is φ = 21147319368.

The previous prime is 21315155359. The next prime is 21315155371. The reversal of 21315155363 is 36355151312.

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 21315155363 - 2² = 21315155359 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21315155963) 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, 83917808 + ... + 83918061.

It is an arithmetic number, because the mean of its divisors is an integer number (5370747840).

Almost surely, 2^21315155363 is an apocalyptic number.

21315155363 is a deficient number, since it is larger than the sum of its proper divisors (167835997).

21315155363 is a wasteful number, since it uses less digits than its factorization.

21315155363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167835996.

The product of its digits is 40500, while the sum is 35.

The spelling of 21315155363 in words is "twenty-one billion, three hundred fifteen million, one hundred fifty-five thousand, three hundred sixty-three".