1678650721 has 8 divisors (see below), whose sum is σ = 1831593600. Its totient is φ = 1525764240.

The previous prime is 1678650683. The next prime is 1678650733. The reversal of 1678650721 is 1270568761.

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

It is not a de Polignac number, because 1678650721 - 2²¹ = 1676553569 is a prime.

It is a super-2 number, since 2×1678650721² = 5635736486227639682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1678650781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69960 + ... + 90838.

It is an arithmetic number, because the mean of its divisors is an integer number (228949200).

Almost surely, 2^1678650721 is an apocalyptic number.

1678650721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1678650721 is a deficient number, since it is larger than the sum of its proper divisors (152942879).

1678650721 is a wasteful number, since it uses less digits than its factorization.

1678650721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28199.

The product of its (nonzero) digits is 141120, while the sum is 43.

The square root of 1678650721 is about 40971.3402392453. The cubic root of 1678650721 is about 1188.4660509853.

The spelling of 1678650721 in words is "one billion, six hundred seventy-eight million, six hundred fifty thousand, seven hundred twenty-one".