2138729 has 4 divisors (see below), whose sum is σ = 2145876. Its totient is φ = 2131584.

The previous prime is 2138713. The next prime is 2138737. The reversal of 2138729 is 9278312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 102400 + 2036329 = 320^2 + 1427^2 .

It is a cyclic number.

It is not a de Polignac number, because 2138729 - 2⁴ = 2138713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2138695 and 2138704.

It is not an unprimeable number, because it can be changed into a prime (2138749) 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, 3104 + ... + 3729.

It is an arithmetic number, because the mean of its divisors is an integer number (536469).

2^2138729 is an apocalyptic number.

It is an amenable number.

2138729 is a deficient number, since it is larger than the sum of its proper divisors (7147).

2138729 is an equidigital number, since it uses as much as digits as its factorization.

2138729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7146.

The product of its digits is 6048, while the sum is 32.

The square root of 2138729 is about 1462.4394004539. The cubic root of 2138729 is about 128.8403569703.

The spelling of 2138729 in words is "two million, one hundred thirty-eight thousand, seven hundred twenty-nine".