20071639 has 4 divisors (see below), whose sum is σ = 22939024. Its totient is φ = 17204256.

The previous prime is 20071637. The next prime is 20071643. The reversal of 20071639 is 93617002.

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

It is a cyclic number.

It is not a de Polignac number, because 20071639 - 2¹ = 20071637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20071631) 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, 1433682 + ... + 1433695.

It is an arithmetic number, because the mean of its divisors is an integer number (5734756).

Almost surely, 2^20071639 is an apocalyptic number.

20071639 is a deficient number, since it is larger than the sum of its proper divisors (2867385).

20071639 is an equidigital number, since it uses as much as digits as its factorization.

20071639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2867384.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 20071639 is about 4480.1382791159. The cubic root of 20071639 is about 271.7654724008.

The spelling of 20071639 in words is "twenty million, seventy-one thousand, six hundred thirty-nine".