678883021 has 2 divisors, whose sum is σ = 678883022. Its totient is φ = 678883020.

The previous prime is 678882983. The next prime is 678883033. The reversal of 678883021 is 120388876.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 639381796 + 39501225 = 25286^2 + 6285^2 .

It is a cyclic number.

It is not a de Polignac number, because 678883021 - 2¹¹ = 678880973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678883421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339441510 + 339441511.

It is an arithmetic number, because the mean of its divisors is an integer number (339441511).

Almost surely, 2^678883021 is an apocalyptic number.

It is an amenable number.

678883021 is a deficient number, since it is larger than the sum of its proper divisors (1).

678883021 is an equidigital number, since it uses as much as digits as its factorization.

678883021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129024, while the sum is 43.

The square root of 678883021 is about 26055.3837239063. The cubic root of 678883021 is about 878.8841836551.

The spelling of 678883021 in words is "six hundred seventy-eight million, eight hundred eighty-three thousand, twenty-one".