21171564803 has 2 divisors, whose sum is σ = 21171564804. Its totient is φ = 21171564802.

The previous prime is 21171564727. The next prime is 21171564809. The reversal of 21171564803 is 30846517112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21171564803 - 2³⁴ = 3991695619 is a prime.

It is not a weakly prime, because it can be changed into another prime (21171564809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585782401 + 10585782402.

It is an arithmetic number, because the mean of its divisors is an integer number (10585782402).

Almost surely, 2^21171564803 is an apocalyptic number.

21171564803 is a deficient number, since it is larger than the sum of its proper divisors (1).

21171564803 is an equidigital number, since it uses as much as digits as its factorization.

21171564803 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 38.

The spelling of 21171564803 in words is "twenty-one billion, one hundred seventy-one million, five hundred sixty-four thousand, eight hundred three".