20430551 has 2 divisors, whose sum is σ = 20430552. Its totient is φ = 20430550.

The previous prime is 20430541. The next prime is 20430563. The reversal of 20430551 is 15503402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20430551 - 2²² = 16236247 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20430541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10215275 + 10215276.

It is an arithmetic number, because the mean of its divisors is an integer number (10215276).

Almost surely, 2^20430551 is an apocalyptic number.

20430551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20430551 is an equidigital number, since it uses as much as digits as its factorization.

20430551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 20430551 is about 4520.0167035090. The cubic root of 20430551 is about 273.3757745254.

Adding to 20430551 its reverse (15503402), we get a palindrome (35933953).

The spelling of 20430551 in words is "twenty million, four hundred thirty thousand, five hundred fifty-one".