509451721920 has 168 divisors, whose sum is σ = 1785364482096. Its totient is φ = 133290473472.

The previous prime is 509451721897. The next prime is 509451721921. The reversal of 509451721920 is 29127154905.

509451721920 is a `hidden beast` number, since 5 + 0 + 9 + 451 + 7 + 2 + 192 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (509451721921) 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 23 ways as a sum of consecutive naturals, for example, 1516162 + ... + 1821441.

Almost surely, 2^509451721920 is an apocalyptic number.

It is an amenable number.

509451721920 is an abundant number, since it is smaller than the sum of its proper divisors (1275912760176).

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

509451721920 is a wasteful number, since it uses less digits than its factorization.

509451721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3337679 (or 3337666 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The spelling of 509451721920 in words is "five hundred nine billion, four hundred fifty-one million, seven hundred twenty-one thousand, nine hundred twenty".