21405030320 has 20 divisors (see below), whose sum is σ = 49766695680. Its totient is φ = 8562012096.

The previous prime is 21405030307. The next prime is 21405030331. The reversal of 21405030320 is 2303050412.

It is a happy number.

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

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21405030292 and 21405030301.

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, 133781360 + ... + 133781519.

It is an arithmetic number, because the mean of its divisors is an integer number (2488334784).

Almost surely, 2^21405030320 is an apocalyptic number.

21405030320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21405030320 is an abundant number, since it is smaller than the sum of its proper divisors (28361665360).

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

21405030320 is a wasteful number, since it uses less digits than its factorization.

21405030320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267562892 (or 267562886 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

Adding to 21405030320 its reverse (2303050412), we get a palindrome (23708080732).

The spelling of 21405030320 in words is "twenty-one billion, four hundred five million, thirty thousand, three hundred twenty".