18735721420 has 48 divisors (see below), whose sum is σ = 44864009568. Its totient is φ = 6510873600.

The previous prime is 18735721397. The next prime is 18735721421. The reversal of 18735721420 is 2412753781.

It is not an unprimeable number, because it can be changed into a prime (18735721421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2115006 + ... + 2123845.

It is an arithmetic number, because the mean of its divisors is an integer number (934666866).

Almost surely, 2^18735721420 is an apocalyptic number.

18735721420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18735721420 is an abundant number, since it is smaller than the sum of its proper divisors (26128288148).

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

18735721420 is a wasteful number, since it uses less digits than its factorization.

18735721420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4238890 (or 4238888 counting only the distinct ones).

The product of its (nonzero) digits is 94080, while the sum is 40.

The spelling of 18735721420 in words is "eighteen billion, seven hundred thirty-five million, seven hundred twenty-one thousand, four hundred twenty".