21421500425 has 24 divisors (see below), whose sum is σ = 28653332736. Its totient is φ = 15792747840.

The previous prime is 21421500421. The next prime is 21421500449. The reversal of 21421500425 is 52400512412.

It is not a de Polignac number, because 21421500425 - 2² = 21421500421 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21421500394 and 21421500403.

It is not an unprimeable number, because it can be changed into a prime (21421500421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 142982 + ... + 251568.

It is an arithmetic number, because the mean of its divisors is an integer number (1193888864).

Almost surely, 2^21421500425 is an apocalyptic number.

21421500425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21421500425 is a deficient number, since it is larger than the sum of its proper divisors (7231832311).

21421500425 is a wasteful number, since it uses less digits than its factorization.

21421500425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109217 (or 109212 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 26.

The spelling of 21421500425 in words is "twenty-one billion, four hundred twenty-one million, five hundred thousand, four hundred twenty-five".