20908651 has 2 divisors, whose sum is σ = 20908652. Its totient is φ = 20908650.

The previous prime is 20908649. The next prime is 20908669. The reversal of 20908651 is 15680902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20908651 - 2¹ = 20908649 is a prime.

Together with 20908649, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20908631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10454325 + 10454326.

It is an arithmetic number, because the mean of its divisors is an integer number (10454326).

Almost surely, 2^20908651 is an apocalyptic number.

20908651 is a deficient number, since it is larger than the sum of its proper divisors (1).

20908651 is an equidigital number, since it uses as much as digits as its factorization.

20908651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 20908651 is about 4572.5978393032. The cubic root of 20908651 is about 275.4917965548.

The spelling of 20908651 in words is "twenty million, nine hundred eight thousand, six hundred fifty-one".