684021545 has 8 divisors (see below), whose sum is σ = 821399496. Its totient is φ = 546834816.

The previous prime is 684021493. The next prime is 684021557. The reversal of 684021545 is 545120486.

It can be written as a sum of positive squares in 4 ways, for example, as 207734569 + 476286976 = 14413^2 + 21824^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684021545 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39812 + ... + 54341.

It is an arithmetic number, because the mean of its divisors is an integer number (102674937).

Almost surely, 2^684021545 is an apocalyptic number.

It is an amenable number.

684021545 is a deficient number, since it is larger than the sum of its proper divisors (137377951).

684021545 is a wasteful number, since it uses less digits than its factorization.

684021545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95611.

The product of its (nonzero) digits is 38400, while the sum is 35.

The square root of 684021545 is about 26153.8055548327. The cubic root of 684021545 is about 881.0960623760.

The spelling of 684021545 in words is "six hundred eighty-four million, twenty-one thousand, five hundred forty-five".