20701639 has 4 divisors (see below), whose sum is σ = 23659024. Its totient is φ = 17744256.

The previous prime is 20701627. The next prime is 20701649. The reversal of 20701639 is 93610702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93610702 = 2 ⋅46805351.

It is a cyclic number.

It is not a de Polignac number, because 20701639 - 2⁷ = 20701511 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 (20701609) 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, 1478682 + ... + 1478695.

It is an arithmetic number, because the mean of its divisors is an integer number (5914756).

Almost surely, 2^20701639 is an apocalyptic number.

20701639 is a deficient number, since it is larger than the sum of its proper divisors (2957385).

20701639 is an equidigital number, since it uses as much as digits as its factorization.

20701639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2957384.

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

The square root of 20701639 is about 4549.9053836316. The cubic root of 20701639 is about 274.5795846007.

The spelling of 20701639 in words is "twenty million, seven hundred one thousand, six hundred thirty-nine".