20428531 has 8 divisors (see below), whose sum is σ = 21588480. Its totient is φ = 19291272.

The previous prime is 20428523. The next prime is 20428549. The reversal of 20428531 is 13582402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20428531 - 2³ = 20428523 is a prime.

It is a super-2 number, since 2×20428531² = 834649757635922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20428496 and 20428505.

It is not an unprimeable number, because it can be changed into a prime (20428511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3805 + ... + 7438.

It is an arithmetic number, because the mean of its divisors is an integer number (2698560).

Almost surely, 2^20428531 is an apocalyptic number.

20428531 is a deficient number, since it is larger than the sum of its proper divisors (1159949).

20428531 is a wasteful number, since it uses less digits than its factorization.

20428531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11345.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 20428531 is about 4519.7932474838. The cubic root of 20428531 is about 273.3667645341.

The spelling of 20428531 in words is "twenty million, four hundred twenty-eight thousand, five hundred thirty-one".