21256133370 has 16 divisors (see below), whose sum is σ = 51014720160. Its totient is φ = 5668302224.

The previous prime is 21256133323. The next prime is 21256133377. The reversal of 21256133370 is 7333165212.

It is not an unprimeable number, because it can be changed into a prime (21256133377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 354268860 + ... + 354268919.

It is an arithmetic number, because the mean of its divisors is an integer number (3188420010).

Almost surely, 2^21256133370 is an apocalyptic number.

21256133370 is an abundant number, since it is smaller than the sum of its proper divisors (29758586790).

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

21256133370 is a wasteful number, since it uses less digits than its factorization.

21256133370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708537789.

The product of its (nonzero) digits is 22680, while the sum is 33.

Adding to 21256133370 its reverse (7333165212), we get a palindrome (28589298582).

The spelling of 21256133370 in words is "twenty-one billion, two hundred fifty-six million, one hundred thirty-three thousand, three hundred seventy".