20398457 has 4 divisors (see below), whose sum is σ = 21472080. Its totient is φ = 19324836.

The previous prime is 20398409. The next prime is 20398459. The reversal of 20398457 is 75489302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20398457 - 2⁶ = 20398393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20398457.

It is not an unprimeable number, because it can be changed into a prime (20398459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 536783 + ... + 536820.

It is an arithmetic number, because the mean of its divisors is an integer number (5368020).

Almost surely, 2^20398457 is an apocalyptic number.

It is an amenable number.

20398457 is a deficient number, since it is larger than the sum of its proper divisors (1073623).

20398457 is a wasteful number, since it uses less digits than its factorization.

20398457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073622.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 20398457 is about 4516.4651000534. The cubic root of 20398457 is about 273.2325524087.

The spelling of 20398457 in words is "twenty million, three hundred ninety-eight thousand, four hundred fifty-seven".