1967856256809 has 45 divisors (see below), whose sum is σ = 2978828537223. Its totient is φ = 1294641277488.

The previous prime is 1967856256789. The next prime is 1967856256811. The reversal of 1967856256809 is 9086526587691.

The square root of 1967856256809 is 1402803.

It is a perfect power (a square), and thus also a powerful number.

1967856256809 is a `hidden beast` number, since 1 + 9 + 6 + 7 + 8 + 56 + 2 + 568 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 423234819225 + 1544621437584 = 650565^2 + 1242828^2 .

It is not a de Polignac number, because 1967856256809 - 2⁵ = 1967856256777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1967856252809) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 997391947 + ... + 997393919.

Almost surely, 2^{1967856256809} is an apocalyptic number.

1967856256809 is the 1402803-rd square number.

1967856256809 is the 701402-nd centered octagonal number.

It is an amenable number.

1967856256809 is a deficient number, since it is larger than the sum of its proper divisors (1010972280414).

1967856256809 is an frugal number, since it uses more digits than its factorization.

1967856256809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4116 (or 2055 counting only the distinct ones).

The product of its (nonzero) digits is 391910400, while the sum is 72.

The spelling of 1967856256809 in words is "one trillion, nine hundred sixty-seven billion, eight hundred fifty-six million, two hundred fifty-six thousand, eight hundred nine".