2638729 has 4 divisors (see below), whose sum is σ = 2710084. Its totient is φ = 2567376.

The previous prime is 2638717. The next prime is 2638747. The reversal of 2638729 is 9278362.

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 1567504 + 1071225 = 1252^2 + 1035^2 .

It is a cyclic number.

It is not a de Polignac number, because 2638729 - 2⁵ = 2638697 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 71317 = 2638729 / (2 + 6 + 3 + 8 + 7 + 2 + 9).

It is a d-powerful number, because it can be written as 2¹³ + 6 + 3⁷ + 8⁷ + 7³ + 2¹⁹ + 9⁴ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2638529) 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, 35622 + ... + 35695.

It is an arithmetic number, because the mean of its divisors is an integer number (677521).

2^2638729 is an apocalyptic number.

It is an amenable number.

2638729 is a deficient number, since it is larger than the sum of its proper divisors (71355).

2638729 is an equidigital number, since it uses as much as digits as its factorization.

2638729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71354.

The product of its digits is 36288, while the sum is 37.

The square root of 2638729 is about 1624.4165106277. The cubic root of 2638729 is about 138.1862813734.

2638729 divided by its sum of digits (37) gives a palindrome (71317).

The spelling of 2638729 in words is "two million, six hundred thirty-eight thousand, seven hundred twenty-nine".