20213939 has 4 divisors (see below), whose sum is σ = 20361624. Its totient is φ = 20066256.

The previous prime is 20213923. The next prime is 20213959. The reversal of 20213939 is 93931202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93931202 = 2 ⋅46965601.

It is a cyclic number.

It is not a de Polignac number, because 20213939 - 2⁴ = 20213923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20213959) 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, 73637 + ... + 73910.

It is an arithmetic number, because the mean of its divisors is an integer number (5090406).

Almost surely, 2^20213939 is an apocalyptic number.

20213939 is a deficient number, since it is larger than the sum of its proper divisors (147685).

20213939 is a wasteful number, since it uses less digits than its factorization.

20213939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147684.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 20213939 is about 4495.9914368246. The cubic root of 20213939 is about 272.4061972682.

It can be divided in two parts, 202 and 13939, that added together give a palindrome (14141).

The spelling of 20213939 in words is "twenty million, two hundred thirteen thousand, nine hundred thirty-nine".