21255025782 has 8 divisors (see below), whose sum is σ = 42510051576. Its totient is φ = 7085008592.

The previous prime is 21255025763. The next prime is 21255025787. The reversal of 21255025782 is 28752055212.

It is a sphenic number, since it is the product of 3 distinct primes.

21255025782 is an admirable number.

It is a super-2 number, since 2×21255025782² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21255025782.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255025787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1771252143 + ... + 1771252154.

It is an arithmetic number, because the mean of its divisors is an integer number (5313756447).

Almost surely, 2^21255025782 is an apocalyptic number.

21255025782 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21255025782 is a wasteful number, since it uses less digits than its factorization.

21255025782 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3542504302.

The product of its (nonzero) digits is 112000, while the sum is 39.

The spelling of 21255025782 in words is "twenty-one billion, two hundred fifty-five million, twenty-five thousand, seven hundred eighty-two".