21042401205 has 32 divisors (see below), whose sum is σ = 38500533504. Its totient is φ = 9613633536.

The previous prime is 21042401203. The next prime is 21042401249. The reversal of 21042401205 is 50210424012.

It is not a de Polignac number, because 21042401205 - 2¹ = 21042401203 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042401201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 119139 + ... + 237231.

It is an arithmetic number, because the mean of its divisors is an integer number (1203141672).

Almost surely, 2^21042401205 is an apocalyptic number.

It is an amenable number.

21042401205 is a deficient number, since it is larger than the sum of its proper divisors (17458132299).

21042401205 is a wasteful number, since it uses less digits than its factorization.

21042401205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119805.

The product of its (nonzero) digits is 640, while the sum is 21.

Adding to 21042401205 its reverse (50210424012), we get a palindrome (71252825217).

The spelling of 21042401205 in words is "twenty-one billion, forty-two million, four hundred one thousand, two hundred five".