20781764642 has 8 divisors (see below), whose sum is σ = 31215527616. Its totient is φ = 10376588772.

The previous prime is 20781764629. The next prime is 20781764657. The reversal of 20781764642 is 24646718702.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7144958 + ... + 7147865.

It is an arithmetic number, because the mean of its divisors is an integer number (3901940952).

Almost surely, 2^20781764642 is an apocalyptic number.

20781764642 is a deficient number, since it is larger than the sum of its proper divisors (10433762974).

20781764642 is a wasteful number, since it uses less digits than its factorization.

20781764642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14293552.

The product of its (nonzero) digits is 903168, while the sum is 47.

The spelling of 20781764642 in words is "twenty billion, seven hundred eighty-one million, seven hundred sixty-four thousand, six hundred forty-two".