21430477520 has 20 divisors (see below), whose sum is σ = 49825860420. Its totient is φ = 8572190976.

The previous prime is 21430477513. The next prime is 21430477531. The reversal of 21430477520 is 2577403412.

It can be written as a sum of positive squares in 2 ways, for example, as 9830325904 + 11600151616 = 99148^2 + 107704^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133940405 + ... + 133940564.

It is an arithmetic number, because the mean of its divisors is an integer number (2491293021).

Almost surely, 2^21430477520 is an apocalyptic number.

21430477520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21430477520 is an abundant number, since it is smaller than the sum of its proper divisors (28395382900).

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

21430477520 is a wasteful number, since it uses less digits than its factorization.

21430477520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267880982 (or 267880976 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 35.

The spelling of 21430477520 in words is "twenty-one billion, four hundred thirty million, four hundred seventy-seven thousand, five hundred twenty".