21041423551 has 4 divisors (see below), whose sum is σ = 21610110712. Its totient is φ = 20472736392.

The previous prime is 21041423539. The next prime is 21041423563. The reversal of 21041423551 is 15532414012.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21041423539) and next prime (21041423563).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21041423551 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 (21041423581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 284343525 + ... + 284343598.

It is an arithmetic number, because the mean of its divisors is an integer number (5402527678).

Almost surely, 2^21041423551 is an apocalyptic number.

21041423551 is a deficient number, since it is larger than the sum of its proper divisors (568687161).

21041423551 is an equidigital number, since it uses as much as digits as its factorization.

21041423551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568687160.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21041423551 its reverse (15532414012), we get a palindrome (36573837563).

The spelling of 21041423551 in words is "twenty-one billion, forty-one million, four hundred twenty-three thousand, five hundred fifty-one".