21138356047 has 8 divisors (see below), whose sum is σ = 21492619920. Its totient is φ = 20784341760.

The previous prime is 21138356027. The next prime is 21138356081. The reversal of 21138356047 is 74065383112.

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

It is a cyclic number.

It is not a de Polignac number, because 21138356047 - 2³¹ = 18990872399 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 (21138356027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112479 + ... + 234367.

It is an arithmetic number, because the mean of its divisors is an integer number (2686577490).

Almost surely, 2^21138356047 is an apocalyptic number.

21138356047 is a deficient number, since it is larger than the sum of its proper divisors (354263873).

21138356047 is a wasteful number, since it uses less digits than its factorization.

21138356047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124793.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21138356047 in words is "twenty-one billion, one hundred thirty-eight million, three hundred fifty-six thousand, forty-seven".