21151662243 has 4 divisors (see below), whose sum is σ = 28202216328. Its totient is φ = 14101108160.

The previous prime is 21151662211. The next prime is 21151662307. The reversal of 21151662243 is 34226615112.

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 21151662243 - 2⁵ = 21151662211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21151662643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3525277038 + ... + 3525277043.

It is an arithmetic number, because the mean of its divisors is an integer number (7050554082).

Almost surely, 2^21151662243 is an apocalyptic number.

21151662243 is a deficient number, since it is larger than the sum of its proper divisors (7050554085).

21151662243 is an equidigital number, since it uses as much as digits as its factorization.

21151662243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7050554084.

The product of its digits is 17280, while the sum is 33.

The spelling of 21151662243 in words is "twenty-one billion, one hundred fifty-one million, six hundred sixty-two thousand, two hundred forty-three".