21213313551 has 6 divisors (see below), whose sum is σ = 30641452920. Its totient is φ = 14142209028.

The previous prime is 21213313549. The next prime is 21213313573. The reversal of 21213313551 is 15531331212.

It is not a de Polignac number, because 21213313551 - 2¹ = 21213313549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213313151) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178517411 + ... + 1178517428.

It is an arithmetic number, because the mean of its divisors is an integer number (5106908820).

Almost surely, 2^21213313551 is an apocalyptic number.

21213313551 is a deficient number, since it is larger than the sum of its proper divisors (9428139369).

21213313551 is a wasteful number, since it uses less digits than its factorization.

21213313551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2357034845 (or 2357034842 counting only the distinct ones).

The product of its digits is 2700, while the sum is 27.

Adding to 21213313551 its reverse (15531331212), we get a palindrome (36744644763).

The spelling of 21213313551 in words is "twenty-one billion, two hundred thirteen million, three hundred thirteen thousand, five hundred fifty-one".