21535156364065 has 8 divisors (see below), whose sum is σ = 26006787559080. Its totient is φ = 17118391809792.

The previous prime is 21535156364027. The next prime is 21535156364081. The reversal of 21535156364065 is 56046365153512.

It can be written as a sum of positive squares in 4 ways, for example, as 1006572764961 + 20528583599104 = 1003281^2 + 4530848^2 .

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 21535156364065 - 2⁴³ = 12739063341857 is a prime.

It is an unprimeable number.

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, 13716659320 + ... + 13716660889.

It is an arithmetic number, because the mean of its divisors is an integer number (3250848444885).

Almost surely, 2^{21535156364065} is an apocalyptic number.

It is an amenable number.

21535156364065 is a deficient number, since it is larger than the sum of its proper divisors (4471631195015).

21535156364065 is a wasteful number, since it uses less digits than its factorization.

21535156364065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27433320371.

The product of its (nonzero) digits is 9720000, while the sum is 52.

The spelling of 21535156364065 in words is "twenty-one trillion, five hundred thirty-five billion, one hundred fifty-six million, three hundred sixty-four thousand, sixty-five".