20435257 has 2 divisors, whose sum is σ = 20435258. Its totient is φ = 20435256.

The previous prime is 20435251. The next prime is 20435287. The reversal of 20435257 is 75253402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17732521 + 2702736 = 4211^2 + 1644^2 .

It is a cyclic number.

It is not a de Polignac number, because 20435257 - 2²³ = 12046649 is a prime.

It is a super-3 number, since 3×20435257³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20435251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10217628 + 10217629.

It is an arithmetic number, because the mean of its divisors is an integer number (10217629).

Almost surely, 2^20435257 is an apocalyptic number.

It is an amenable number.

20435257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20435257 is an equidigital number, since it uses as much as digits as its factorization.

20435257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8400, while the sum is 28.

The square root of 20435257 is about 4520.5372468325. The cubic root of 20435257 is about 273.3967628259.

Adding to 20435257 its reverse (75253402), we get a palindrome (95688659).

The spelling of 20435257 in words is "twenty million, four hundred thirty-five thousand, two hundred fifty-seven".