20939391 has 40 divisors (see below), whose sum is σ = 34708608. Its totient is φ = 12474000.

The previous prime is 20939389. The next prime is 20939419. The reversal of 20939391 is 19393902.

It is not a de Polignac number, because 20939391 - 2¹ = 20939389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20939341) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 63096 + ... + 63426.

Almost surely, 2^20939391 is an apocalyptic number.

20939391 is a deficient number, since it is larger than the sum of its proper divisors (13769217).

20939391 is a wasteful number, since it uses less digits than its factorization.

20939391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425 (or 416 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 36.

The square root of 20939391 is about 4575.9579324989. The cubic root of 20939391 is about 275.6267402361.

The spelling of 20939391 in words is "twenty million, nine hundred thirty-nine thousand, three hundred ninety-one".