1865139221401 has 9 divisors (see below), whose sum is σ = 1968498420501. Its totient is φ = 1766949416604.

The previous prime is 1865139221369. The next prime is 1865139221417. The reversal of 1865139221401 is 1041229315681.

The square root of 1865139221401 is 1365701.

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

It is not a de Polignac number, because 1865139221401 - 2⁵ = 1865139221369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1865139221801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 25912380 + ... + 25984258.

Almost surely, 2^{1865139221401} is an apocalyptic number.

1865139221401 is the 1365701-st square number.

1865139221401 is the 682851-st centered octagonal number.

It is an amenable number.

1865139221401 is a deficient number, since it is larger than the sum of its proper divisors (103359199100).

1865139221401 is an frugal number, since it uses more digits than its factorization.

1865139221401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143796 (or 71898 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 43.

The spelling of 1865139221401 in words is "one trillion, eight hundred sixty-five billion, one hundred thirty-nine million, two hundred twenty-one thousand, four hundred one".