21421245793 has 8 divisors (see below), whose sum is σ = 22006708200. Its totient is φ = 20836126080.

The previous prime is 21421245787. The next prime is 21421245841. The reversal of 21421245793 is 39754212412.

It can be written as a sum of positive squares in 4 ways, for example, as 5320681249 + 16100564544 = 72943^2 + 126888^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21421245793 - 2¹³ = 21421237601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21421245193) 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, 43683 + ... + 211543.

It is an arithmetic number, because the mean of its divisors is an integer number (2750838525).

Almost surely, 2^21421245793 is an apocalyptic number.

It is an amenable number.

21421245793 is a deficient number, since it is larger than the sum of its proper divisors (585462407).

21421245793 is a wasteful number, since it uses less digits than its factorization.

21421245793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171347.

The product of its digits is 120960, while the sum is 40.

The spelling of 21421245793 in words is "twenty-one billion, four hundred twenty-one million, two hundred forty-five thousand, seven hundred ninety-three".