20278013 has 12 divisors (see below), whose sum is σ = 23916060. Its totient is φ = 17140032.

The previous prime is 20278003. The next prime is 20278021. The reversal of 20278013 is 31087202.

It can be written as a sum of positive squares in 2 ways, for example, as 8076964 + 12201049 = 2842^2 + 3493^2 .

It is not a de Polignac number, because 20278013 - 2¹⁰ = 20276989 is a prime.

It is a super-2 number, since 2×20278013² = 822395622456338, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20278013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20278003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 743 + ... + 6411.

It is an arithmetic number, because the mean of its divisors is an integer number (1993005).

Almost surely, 2^20278013 is an apocalyptic number.

It is an amenable number.

20278013 is a deficient number, since it is larger than the sum of its proper divisors (3638047).

20278013 is an equidigital number, since it uses as much as digits as its factorization.

20278013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5756 (or 5749 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 20278013 is about 4503.1114798548. Note that the first 3 decimals coincide. The cubic root of 20278013 is about 272.6937174306.

The spelling of 20278013 in words is "twenty million, two hundred seventy-eight thousand, thirteen".