21090715839 has 24 divisors (see below), whose sum is σ = 31564667472. Its totient is φ = 13559374080.

The previous prime is 21090715817. The next prime is 21090715853. The reversal of 21090715839 is 93851709012.

It is not a de Polignac number, because 21090715839 - 2¹⁵ = 21090683071 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21090715794 and 21090715803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090715339) 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 23 ways as a sum of consecutive naturals, for example, 242617 + ... + 317874.

It is an arithmetic number, because the mean of its divisors is an integer number (1315194478).

Almost surely, 2^21090715839 is an apocalyptic number.

21090715839 is a deficient number, since it is larger than the sum of its proper divisors (10473951633).

21090715839 is a wasteful number, since it uses less digits than its factorization.

21090715839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 560647 (or 560644 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The spelling of 21090715839 in words is "twenty-one billion, ninety million, seven hundred fifteen thousand, eight hundred thirty-nine".