21009836250 has 240 divisors, whose sum is σ = 61932406536. Its totient is φ = 5114880000.

The previous prime is 21009836227. The next prime is 21009836261. The reversal of 21009836250 is 5263890012.

21009836250 is a `hidden beast` number, since 21 + 0 + 0 + 9 + 8 + 3 + 625 + 0 = 666.

It can be written as a sum of positive squares in 20 ways, for example, as 13569221169 + 7440615081 = 116487^2 + 86259^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 14185510 + ... + 14186990.

Almost surely, 2^21009836250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21009836250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30966203268).

21009836250 is an abundant number, since it is smaller than the sum of its proper divisors (40922570286).

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

21009836250 is a wasteful number, since it uses less digits than its factorization.

21009836250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1619 (or 1601 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21009836250 in words is "twenty-one billion, nine million, eight hundred thirty-six thousand, two hundred fifty".