21425431520 has 48 divisors (see below), whose sum is σ = 51373093968. Its totient is φ = 8442255360.

The previous prime is 21425431519. The next prime is 21425431561. The reversal of 21425431520 is 2513452412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 988601 + ... + 1010040.

It is an arithmetic number, because the mean of its divisors is an integer number (1070272791).

Almost surely, 2^21425431520 is an apocalyptic number.

21425431520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21425431520 is an abundant number, since it is smaller than the sum of its proper divisors (29947662448).

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

21425431520 is a wasteful number, since it uses less digits than its factorization.

21425431520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1998723 (or 1998715 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 21425431520 its reverse (2513452412), we get a palindrome (23938883932).

The spelling of 21425431520 in words is "twenty-one billion, four hundred twenty-five million, four hundred thirty-one thousand, five hundred twenty".