21250236810 has 256 divisors, whose sum is σ = 61702373376. Its totient is φ = 4623360000.

The previous prime is 21250236803. The next prime is 21250236817. The reversal of 21250236810 is 1863205212.

It is an interprime number because it is at equal distance from previous prime (21250236803) and next prime (21250236817).

It is a super-2 number, since 2×21250236810² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21250236817) by changing a digit.

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 127 ways as a sum of consecutive naturals, for example, 12346750 + ... + 12348470.

It is an arithmetic number, because the mean of its divisors is an integer number (241024896).

Almost surely, 2^21250236810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21250236810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30851186688).

21250236810 is an abundant number, since it is smaller than the sum of its proper divisors (40452136566).

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

21250236810 is a wasteful number, since it uses less digits than its factorization.

21250236810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1861.

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21250236810 in words is "twenty-one billion, two hundred fifty million, two hundred thirty-six thousand, eight hundred ten".