21234156767 has 4 divisors (see below), whose sum is σ = 21284594616. Its totient is φ = 21183718920.

The previous prime is 21234156733. The next prime is 21234156793. The reversal of 21234156767 is 76765143212.

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 21234156767 - 2⁸ = 21234156511 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 (21234150767) 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, 25218293 + ... + 25219134.

It is an arithmetic number, because the mean of its divisors is an integer number (5321148654).

Almost surely, 2^21234156767 is an apocalyptic number.

21234156767 is a deficient number, since it is larger than the sum of its proper divisors (50437849).

21234156767 is an equidigital number, since it uses as much as digits as its factorization.

21234156767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50437848.

The product of its digits is 423360, while the sum is 44.

Adding to 21234156767 its reverse (76765143212), we get a palindrome (97999299979).

The spelling of 21234156767 in words is "twenty-one billion, two hundred thirty-four million, one hundred fifty-six thousand, seven hundred sixty-seven".