13421221820 has 24 divisors (see below), whose sum is σ = 28187447904. Its totient is φ = 5367939776.

The previous prime is 13421221813. The next prime is 13421221831. The reversal of 13421221820 is 2812212431.

It is a super-2 number, since 2×13421221820² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 13421221820.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207857 + ... + 264663.

It is an arithmetic number, because the mean of its divisors is an integer number (1174476996).

Almost surely, 2^13421221820 is an apocalyptic number.

13421221820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13421221820 is an abundant number, since it is smaller than the sum of its proper divisors (14766226084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13421221820 is a wasteful number, since it uses less digits than its factorization.

13421221820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68629 (or 68627 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The spelling of 13421221820 in words is "thirteen billion, four hundred twenty-one million, two hundred twenty-one thousand, eight hundred twenty".