21345578169 has 16 divisors (see below), whose sum is σ = 28785154944. Its totient is φ = 14068656000.

The previous prime is 21345578167. The next prime is 21345578197. The reversal of 21345578169 is 96187554312.

It is not a de Polignac number, because 21345578169 - 2¹ = 21345578167 is a prime.

It is a super-2 number, since 2×21345578169² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21345578167) 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 15 ways as a sum of consecutive naturals, for example, 128239 + ... + 243179.

It is an arithmetic number, because the mean of its divisors is an integer number (1799072184).

Almost surely, 2^21345578169 is an apocalyptic number.

It is an amenable number.

21345578169 is a deficient number, since it is larger than the sum of its proper divisors (7439576775).

21345578169 is a wasteful number, since it uses less digits than its factorization.

21345578169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115648.

The product of its digits is 1814400, while the sum is 51.

The spelling of 21345578169 in words is "twenty-one billion, three hundred forty-five million, five hundred seventy-eight thousand, one hundred sixty-nine".