21355910785 has 8 divisors (see below), whose sum is σ = 27956828736. Its totient is φ = 15531571440.

The previous prime is 21355910773. The next prime is 21355910801. The reversal of 21355910785 is 58701955312.

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

It is not a de Polignac number, because 21355910785 - 2¹⁹ = 21355386497 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194144589 + ... + 194144698.

It is an arithmetic number, because the mean of its divisors is an integer number (3494603592).

Almost surely, 2^21355910785 is an apocalyptic number.

It is an amenable number.

21355910785 is a deficient number, since it is larger than the sum of its proper divisors (6600917951).

21355910785 is a wasteful number, since it uses less digits than its factorization.

21355910785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388289303.

The product of its (nonzero) digits is 378000, while the sum is 46.

The spelling of 21355910785 in words is "twenty-one billion, three hundred fifty-five million, nine hundred ten thousand, seven hundred eighty-five".