21515740435138 has 16 divisors (see below), whose sum is σ = 32978001925440. Its totient is φ = 10525386398800.

The previous prime is 21515740435127. The next prime is 21515740435157. The reversal of 21515740435138 is 83153404751512.

It is a junction number, because it is equal to n+sod(n) for n = 21515740435091 and 21515740435100.

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, 578299333 + ... + 578336536.

It is an arithmetic number, because the mean of its divisors is an integer number (2061125120340).

Almost surely, 2^{21515740435138} is an apocalyptic number.

21515740435138 is a deficient number, since it is larger than the sum of its proper divisors (11462261490302).

21515740435138 is a wasteful number, since it uses less digits than its factorization.

21515740435138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1156636073.

The product of its (nonzero) digits is 2016000, while the sum is 49.

The spelling of 21515740435138 in words is "twenty-one trillion, five hundred fifteen billion, seven hundred forty million, four hundred thirty-five thousand, one hundred thirty-eight".