21717205183838 has 4 divisors (see below), whose sum is σ = 32575807775760. Its totient is φ = 10858602591918.

The previous prime is 21717205183811. The next prime is 21717205183871. The reversal of 21717205183838 is 83838150271712.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5429301295958 + ... + 5429301295961.

It is an arithmetic number, because the mean of its divisors is an integer number (8143951943940).

Almost surely, 2^{21717205183838} is an apocalyptic number.

21717205183838 is a deficient number, since it is larger than the sum of its proper divisors (10858602591922).

21717205183838 is a wasteful number, since it uses less digits than its factorization.

21717205183838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10858602591921.

The product of its (nonzero) digits is 4515840, while the sum is 56.

The spelling of 21717205183838 in words is "twenty-one trillion, seven hundred seventeen billion, two hundred five million, one hundred eighty-three thousand, eight hundred thirty-eight".