21505733357 has 8 divisors (see below), whose sum is σ = 22653506400. Its totient is φ = 20359549584.

The previous prime is 21505733339. The next prime is 21505733371. The reversal of 21505733357 is 75333750512.

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 21505733357 - 2²² = 21501539053 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 (21505733387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 369482 + ... + 423707.

It is an arithmetic number, because the mean of its divisors is an integer number (2831688300).

Almost surely, 2^21505733357 is an apocalyptic number.

It is an amenable number.

21505733357 is a deficient number, since it is larger than the sum of its proper divisors (1147773043).

21505733357 is a wasteful number, since it uses less digits than its factorization.

21505733357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 794635.

The product of its (nonzero) digits is 330750, while the sum is 41.

The spelling of 21505733357 in words is "twenty-one billion, five hundred five million, seven hundred thirty-three thousand, three hundred fifty-seven".