1539380721 has 8 divisors (see below), whose sum is σ = 2053352160. Its totient is φ = 1025831552.

The previous prime is 1539380683. The next prime is 1539380723. The reversal of 1539380721 is 1270839351.

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

It is a cyclic number.

It is not a de Polignac number, because 1539380721 - 2¹⁹ = 1538856433 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1539380721.

It is not an unprimeable number, because it can be changed into a prime (1539380723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96960 + ... + 111713.

It is an arithmetic number, because the mean of its divisors is an integer number (256669020).

Almost surely, 2^1539380721 is an apocalyptic number.

It is an amenable number.

1539380721 is a deficient number, since it is larger than the sum of its proper divisors (513971439).

1539380721 is a wasteful number, since it uses less digits than its factorization.

1539380721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211135.

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 1539380721 is about 39234.9426022264. The cubic root of 1539380721 is about 1154.6455365496.

The spelling of 1539380721 in words is "one billion, five hundred thirty-nine million, three hundred eighty thousand, seven hundred twenty-one".