21405204227 has 8 divisors (see below), whose sum is σ = 23409955632. Its totient is φ = 19410256800.

The previous prime is 21405204211. The next prime is 21405204253. The reversal of 21405204227 is 72240250412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21405204227 - 2⁴ = 21405204211 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21405204227.

It is not an unprimeable number, because it can be changed into a prime (21405204277) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2446424 + ... + 2455157.

It is an arithmetic number, because the mean of its divisors is an integer number (2926244454).

Almost surely, 2^21405204227 is an apocalyptic number.

21405204227 is a deficient number, since it is larger than the sum of its proper divisors (2004751405).

21405204227 is a wasteful number, since it uses less digits than its factorization.

21405204227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4901989.

The product of its (nonzero) digits is 8960, while the sum is 29.

Adding to 21405204227 its reverse (72240250412), we get a palindrome (93645454639).

The spelling of 21405204227 in words is "twenty-one billion, four hundred five million, two hundred four thousand, two hundred twenty-seven".