15401221920 has 144 divisors (see below), whose sum is σ = 60064804800. Its totient is φ = 3520276992.

The previous prime is 15401221909. The next prime is 15401221933. The reversal of 15401221920 is 2912210451.

15401221920 is a `hidden beast` number, since 1 + 540 + 12 + 21 + 92 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 753870 + ... + 774029.

It is an arithmetic number, because the mean of its divisors is an integer number (417116700).

Almost surely, 2^15401221920 is an apocalyptic number.

15401221920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15401221920 is an abundant number, since it is smaller than the sum of its proper divisors (44663582880).

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

15401221920 is a wasteful number, since it uses less digits than its factorization.

15401221920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1527927 (or 1527916 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The spelling of 15401221920 in words is "fifteen billion, four hundred one million, two hundred twenty-one thousand, nine hundred twenty".