20661556422 has 32 divisors (see below), whose sum is σ = 46844017920. Its totient is φ = 6022801440.

The previous prime is 20661556417. The next prime is 20661556429. The reversal of 20661556422 is 22465516602.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661556429) 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 15 ways as a sum of consecutive naturals, for example, 6969354 + ... + 6972317.

It is an arithmetic number, because the mean of its divisors is an integer number (1463875560).

Almost surely, 2^20661556422 is an apocalyptic number.

20661556422 is an abundant number, since it is smaller than the sum of its proper divisors (26182461498).

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

20661556422 is a wasteful number, since it uses less digits than its factorization.

20661556422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13941708.

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 20661556422 in words is "twenty billion, six hundred sixty-one million, five hundred fifty-six thousand, four hundred twenty-two".