21061400850 has 288 divisors, whose sum is σ = 66897432576. Its totient is φ = 4650048000.

The previous prime is 21061400819. The next prime is 21061400917. The reversal of 21061400850 is 5800416012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 18297775 + ... + 18298925.

It is an arithmetic number, because the mean of its divisors is an integer number (232282752).

Almost surely, 2^21061400850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21061400850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33448716288).

21061400850 is an abundant number, since it is smaller than the sum of its proper divisors (45836031726).

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

21061400850 is a wasteful number, since it uses less digits than its factorization.

21061400850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1370 (or 1362 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

Adding to 21061400850 its reverse (5800416012), we get a palindrome (26861816862).

The spelling of 21061400850 in words is "twenty-one billion, sixty-one million, four hundred thousand, eight hundred fifty".