20545931 has 4 divisors (see below), whose sum is σ = 23481072. Its totient is φ = 17610792.

The previous prime is 20545919. The next prime is 20545937. The reversal of 20545931 is 13954502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13954502 = 2 ⋅6977251.

It is a cyclic number.

It is not a de Polignac number, because 20545931 - 2²² = 16351627 is a prime.

It is a super-2 number, since 2×20545931² = 844270561313522, 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 = 20545894 and 20545903.

It is not an unprimeable number, because it can be changed into a prime (20545937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1467560 + ... + 1467573.

It is an arithmetic number, because the mean of its divisors is an integer number (5870268).

Almost surely, 2^20545931 is an apocalyptic number.

20545931 is a deficient number, since it is larger than the sum of its proper divisors (2935141).

20545931 is an equidigital number, since it uses as much as digits as its factorization.

20545931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2935140.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 20545931 is about 4532.7619615418. The cubic root of 20545931 is about 273.8894318297.

The spelling of 20545931 in words is "twenty million, five hundred forty-five thousand, nine hundred thirty-one".