20665556394 has 32 divisors (see below), whose sum is σ = 47423771136. Its totient is φ = 5880918000.

The previous prime is 20665556347. The next prime is 20665556437. The reversal of 20665556394 is 49365556602.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 969612 + ... + 990695.

It is an arithmetic number, because the mean of its divisors is an integer number (1481992848).

Almost surely, 2^20665556394 is an apocalyptic number.

20665556394 is an abundant number, since it is smaller than the sum of its proper divisors (26758214742).

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

20665556394 is a wasteful number, since it uses less digits than its factorization.

20665556394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960570.

The product of its (nonzero) digits is 5832000, while the sum is 51.

The spelling of 20665556394 in words is "twenty billion, six hundred sixty-five million, five hundred fifty-six thousand, three hundred ninety-four".