20645031 has 16 divisors (see below), whose sum is σ = 30729600. Its totient is φ = 12220320.

The previous prime is 20644997. The next prime is 20645033. The reversal of 20645031 is 13054602.

It is a happy number.

It is not a de Polignac number, because 20645031 - 2⁷ = 20644903 is a prime.

It is a super-2 number, since 2×20645031² = 852434609981922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20644989 and 20645007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645033) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5856 + ... + 8693.

It is an arithmetic number, because the mean of its divisors is an integer number (1920600).

Almost surely, 2^20645031 is an apocalyptic number.

20645031 is a deficient number, since it is larger than the sum of its proper divisors (10084569).

20645031 is a wasteful number, since it uses less digits than its factorization.

20645031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14606.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 20645031 is about 4543.6803364673. The cubic root of 20645031 is about 274.3290796312.

Adding to 20645031 its reverse (13054602), we get a palindrome (33699633).

The spelling of 20645031 in words is "twenty million, six hundred forty-five thousand, thirty-one".