43739121321 has 81 divisors (see below), whose sum is σ = 77005771479. Its totient is φ = 23851884672.

The previous prime is 43739121319. The next prime is 43739121337. The reversal of 43739121321 is 12312193734.

The square root of 43739121321 is 209139.

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

43739121321 is a `hidden beast` number, since 4 + 37 + 391 + 213 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4904901225 + 38834220096 = 70035^2 + 197064^2 .

It is not a de Polignac number, because 43739121321 - 2¹ = 43739121319 is a prime.

It is a super-3 number, since 3×43739121321³ (a number of 33 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (43739123321) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 101013921 + ... + 101014353.

Almost surely, 2^43739121321 is an apocalyptic number.

43739121321 is the 209139-th square number.

43739121321 is the 104570-th centered octagonal number.

It is an amenable number.

43739121321 is a deficient number, since it is larger than the sum of its proper divisors (33266650158).

43739121321 is an equidigital number, since it uses as much as digits as its factorization.

43739121321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932 (or 466 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

Multiplying 43739121321 by its sum of digits (36), we get a square (1574608367556 = 1254834²).

The spelling of 43739121321 in words is "forty-three billion, seven hundred thirty-nine million, one hundred twenty-one thousand, three hundred twenty-one".