21403426551 has 8 divisors (see below), whose sum is σ = 30733125360. Its totient is φ = 13171339392.

The previous prime is 21403426543. The next prime is 21403426589. The reversal of 21403426551 is 15562430412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21403426551 - 2³ = 21403426543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403426531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274402866 + ... + 274402943.

It is an arithmetic number, because the mean of its divisors is an integer number (3841640670).

Almost surely, 2^21403426551 is an apocalyptic number.

21403426551 is a deficient number, since it is larger than the sum of its proper divisors (9329698809).

21403426551 is a wasteful number, since it uses less digits than its factorization.

21403426551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548805825.

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 21403426551 its reverse (15562430412), we get a palindrome (36965856963).

The spelling of 21403426551 in words is "twenty-one billion, four hundred three million, four hundred twenty-six thousand, five hundred fifty-one".