21204129973 has 16 divisors (see below), whose sum is σ = 23088784320. Its totient is φ = 19356339456.

The previous prime is 21204129959. The next prime is 21204130069. The reversal of 21204129973 is 37992140212.

It is a cyclic number.

It is not a de Polignac number, because 21204129973 - 2²¹ = 21202032821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204129073) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 803533 + ... + 829501.

It is an arithmetic number, because the mean of its divisors is an integer number (1443049020).

Almost surely, 2^21204129973 is an apocalyptic number.

It is an amenable number.

21204129973 is a deficient number, since it is larger than the sum of its proper divisors (1884654347).

21204129973 is a wasteful number, since it uses less digits than its factorization.

21204129973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26676.

The product of its (nonzero) digits is 54432, while the sum is 40.

The spelling of 21204129973 in words is "twenty-one billion, two hundred four million, one hundred twenty-nine thousand, nine hundred seventy-three".