20870939 has 2 divisors, whose sum is σ = 20870940. Its totient is φ = 20870938.

The previous prime is 20870909. The next prime is 20871001. The reversal of 20870939 is 93907802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20870939 - 2¹² = 20866843 is a prime.

It is not a weakly prime, because it can be changed into another prime (20870909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10435469 + 10435470.

It is an arithmetic number, because the mean of its divisors is an integer number (10435470).

Almost surely, 2^20870939 is an apocalyptic number.

20870939 is a deficient number, since it is larger than the sum of its proper divisors (1).

20870939 is an equidigital number, since it uses as much as digits as its factorization.

20870939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 20870939 is about 4568.4722829410. The cubic root of 20870939 is about 275.3260661248.

It can be divided in two parts, 20870 and 939, that multiplied together give a triangular number (19596930 = T₆₂₆₀).

The spelling of 20870939 in words is "twenty million, eight hundred seventy thousand, nine hundred thirty-nine".