21436516851 has 16 divisors (see below), whose sum is σ = 30091248000. Its totient is φ = 13536643968.

The previous prime is 21436516807. The next prime is 21436516861. The reversal of 21436516851 is 15861563412.

It is not a de Polignac number, because 21436516851 - 2¹⁰ = 21436515827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21436516861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366475 + ... + 420923.

It is an arithmetic number, because the mean of its divisors is an integer number (1880703000).

Almost surely, 2^21436516851 is an apocalyptic number.

21436516851 is a deficient number, since it is larger than the sum of its proper divisors (8654731149).

21436516851 is a wasteful number, since it uses less digits than its factorization.

21436516851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61378.

The product of its digits is 172800, while the sum is 42.

The spelling of 21436516851 in words is "twenty-one billion, four hundred thirty-six million, five hundred sixteen thousand, eight hundred fifty-one".