20624257 has 2 divisors, whose sum is σ = 20624258. Its totient is φ = 20624256.

The previous prime is 20624251. The next prime is 20624287. The reversal of 20624257 is 75242602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17297281 + 3326976 = 4159^2 + 1824^2 .

It is a cyclic number.

It is not a de Polignac number, because 20624257 - 2²³ = 12235649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20624251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10312128 + 10312129.

It is an arithmetic number, because the mean of its divisors is an integer number (10312129).

Almost surely, 2^20624257 is an apocalyptic number.

It is an amenable number.

20624257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20624257 is an equidigital number, since it uses as much as digits as its factorization.

20624257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 20624257 is about 4541.3937288018. The cubic root of 20624257 is about 274.2370344821.

Adding to 20624257 its reverse (75242602), we get a palindrome (95866859).

The spelling of 20624257 in words is "twenty million, six hundred twenty-four thousand, two hundred fifty-seven".