3644959861 has 4 divisors (see below), whose sum is σ = 3694890892. Its totient is φ = 3595028832.

The previous prime is 3644959789. The next prime is 3644959921. The reversal of 3644959861 is 1689594463.

It is a happy number.

3644959861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1689594463 = 277 ⋅6099619.

It can be written as a sum of positive squares in 2 ways, for example, as 3178140625 + 466819236 = 56375^2 + 21606^2 .

It is a cyclic number.

It is not a de Polignac number, because 3644959861 - 2⁹ = 3644959349 is a prime.

It is a super-2 number, since 2×3644959861² = 26571464776602278642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3644959361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24965406 + ... + 24965551.

It is an arithmetic number, because the mean of its divisors is an integer number (923722723).

Almost surely, 2^3644959861 is an apocalyptic number.

It is an amenable number.

3644959861 is a deficient number, since it is larger than the sum of its proper divisors (49931031).

3644959861 is an equidigital number, since it uses as much as digits as its factorization.

3644959861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49931030.

The product of its digits is 5598720, while the sum is 55.

The square root of 3644959861 is about 60373.5029710882. The cubic root of 3644959861 is about 1538.9727028752.

The spelling of 3644959861 in words is "three billion, six hundred forty-four million, nine hundred fifty-nine thousand, eight hundred sixty-one".