21325605640 has 32 divisors (see below), whose sum is σ = 49279443480. Its totient is φ = 8299694592.

The previous prime is 21325605599. The next prime is 21325605649. The reversal of 21325605640 is 4650652312.

It can be written as a sum of positive squares in 4 ways, for example, as 21063877956 + 261727684 = 145134^2 + 16178^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21325605596 and 21325605605.

It is not an unprimeable number, because it can be changed into a prime (21325605649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7203117 + ... + 7206076.

Almost surely, 2^21325605640 is an apocalyptic number.

21325605640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21325605640 is an abundant number, since it is smaller than the sum of its proper divisors (27953837840).

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

21325605640 is a wasteful number, since it uses less digits than its factorization.

21325605640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14409241 (or 14409237 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 34.

The spelling of 21325605640 in words is "twenty-one billion, three hundred twenty-five million, six hundred five thousand, six hundred forty".