20161623666 has 32 divisors (see below), whose sum is σ = 40565161728. Its totient is φ = 6680257920.

The previous prime is 20161623661. The next prime is 20161623673. The reversal of 20161623666 is 66632616102.

It is a super-2 number, since 2×20161623666² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20161623661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3899415 + ... + 3904581.

It is an arithmetic number, because the mean of its divisors is an integer number (1267661304).

Almost surely, 2^20161623666 is an apocalyptic number.

20161623666 is an abundant number, since it is smaller than the sum of its proper divisors (20403538062).

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

20161623666 is a wasteful number, since it uses less digits than its factorization.

20161623666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8946.

The product of its (nonzero) digits is 93312, while the sum is 39.

The spelling of 20161623666 in words is "twenty billion, one hundred sixty-one million, six hundred twenty-three thousand, six hundred sixty-six".