20857709407 has 2 divisors, whose sum is σ = 20857709408. Its totient is φ = 20857709406.

The previous prime is 20857709393. The next prime is 20857709437. The reversal of 20857709407 is 70490775802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20857709407 - 2¹¹ = 20857707359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20857709437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428854703 + 10428854704.

It is an arithmetic number, because the mean of its divisors is an integer number (10428854704).

Almost surely, 2^20857709407 is an apocalyptic number.

20857709407 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857709407 is an equidigital number, since it uses as much as digits as its factorization.

20857709407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 987840, while the sum is 49.

The spelling of 20857709407 in words is "twenty billion, eight hundred fifty-seven million, seven hundred nine thousand, four hundred seven".