1721428555 has 48 divisors (see below), whose sum is σ = 2636655840. Its totient is φ = 1066867200.

The previous prime is 1721428507. The next prime is 1721428559. The reversal of 1721428555 is 5558241271.

It is not a de Polignac number, because 1721428555 - 2²¹ = 1719331403 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1721428559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 486031 + ... + 489559.

It is an arithmetic number, because the mean of its divisors is an integer number (54930330).

Almost surely, 2^1721428555 is an apocalyptic number.

1721428555 is a deficient number, since it is larger than the sum of its proper divisors (915227285).

1721428555 is a wasteful number, since it uses less digits than its factorization.

1721428555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3740 (or 3733 counting only the distinct ones).

The product of its digits is 112000, while the sum is 40.

The square root of 1721428555 is about 41490.1018918971. The cubic root of 1721428555 is about 1198.4768997986.

The spelling of 1721428555 in words is "one billion, seven hundred twenty-one million, four hundred twenty-eight thousand, five hundred fifty-five".