21606641782 has 16 divisors (see below), whose sum is σ = 35425803600. Its totient is φ = 9801900640.

The previous prime is 21606641773. The next prime is 21606641821. The reversal of 21606641782 is 28714660612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 953557 + ... + 975952.

It is an arithmetic number, because the mean of its divisors is an integer number (2214112725).

Almost surely, 2^21606641782 is an apocalyptic number.

21606641782 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21606641782 is a deficient number, since it is larger than the sum of its proper divisors (13819161818).

21606641782 is a wasteful number, since it uses less digits than its factorization.

21606641782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930031.

The product of its (nonzero) digits is 193536, while the sum is 43.

The spelling of 21606641782 in words is "twenty-one billion, six hundred six million, six hundred forty-one thousand, seven hundred eighty-two".