21157587734549 has 8 divisors (see below), whose sum is σ = 24181164667968. Its totient is φ = 18134276901120.

The previous prime is 21157587734501. The next prime is 21157587734639. The reversal of 21157587734549 is 94543778575112.

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 21157587734549 - 2¹⁶ = 21157587669013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157587734449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66354587 + ... + 66672680.

It is an arithmetic number, because the mean of its divisors is an integer number (3022645583496).

Almost surely, 2^{21157587734549} is an apocalyptic number.

It is an amenable number.

21157587734549 is a deficient number, since it is larger than the sum of its proper divisors (3023576933419).

21157587734549 is a wasteful number, since it uses less digits than its factorization.

21157587734549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133049995.

The product of its digits is 296352000, while the sum is 68.

The spelling of 21157587734549 in words is "twenty-one trillion, one hundred fifty-seven billion, five hundred eighty-seven million, seven hundred thirty-four thousand, five hundred forty-nine".