1978693 has 2 divisors, whose sum is σ = 1978694. Its totient is φ = 1978692.

The previous prime is 1978687. The next prime is 1978709. The reversal of 1978693 is 3968791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1119364 + 859329 = 1058^2 + 927^2 .

It is a cyclic number.

It is not a de Polignac number, because 1978693 - 2⁵ = 1978661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989346 + 989347.

It is an arithmetic number, because the mean of its divisors is an integer number (989347).

2^1978693 is an apocalyptic number.

It is an amenable number.

1978693 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978693 is an equidigital number, since it uses as much as digits as its factorization.

1978693 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 43.

The square root of 1978693 is about 1406.6602290532. The cubic root of 1978693 is about 125.5430876955.

The spelling of 1978693 in words is "one million, nine hundred seventy-eight thousand, six hundred ninety-three".