21020620279 has 4 divisors (see below), whose sum is σ = 21286704160. Its totient is φ = 20754536400.

The previous prime is 21020620277. The next prime is 21020620321. The reversal of 21020620279 is 97202602012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21020620279 - 2¹ = 21020620277 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 21020620279.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020620277) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133041822 + ... + 133041979.

It is an arithmetic number, because the mean of its divisors is an integer number (5321676040).

Almost surely, 2^21020620279 is an apocalyptic number.

21020620279 is a deficient number, since it is larger than the sum of its proper divisors (266083881).

21020620279 is an equidigital number, since it uses as much as digits as its factorization.

21020620279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266083880.

The product of its (nonzero) digits is 6048, while the sum is 31.

The spelling of 21020620279 in words is "twenty-one billion, twenty million, six hundred twenty thousand, two hundred seventy-nine".