21121510343 has 4 divisors (see below), whose sum is σ = 21135754248. Its totient is φ = 21107266440.

The previous prime is 21121510337. The next prime is 21121510381. The reversal of 21121510343 is 34301512112.

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 21121510343 - 2¹⁴ = 21121493959 is a prime.

It is a super-2 number, since 2×21121510343² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121519343) 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, 7119728 + ... + 7122693.

It is an arithmetic number, because the mean of its divisors is an integer number (5283938562).

Almost surely, 2^21121510343 is an apocalyptic number.

21121510343 is a deficient number, since it is larger than the sum of its proper divisors (14243905).

21121510343 is a wasteful number, since it uses less digits than its factorization.

21121510343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14243904.

The product of its (nonzero) digits is 720, while the sum is 23.

The spelling of 21121510343 in words is "twenty-one billion, one hundred twenty-one million, five hundred ten thousand, three hundred forty-three".