20278643 has 32 divisors (see below), whose sum is σ = 27095040. Its totient is φ = 14700960.

The previous prime is 20278631. The next prime is 20278649. The reversal of 20278643 is 34687202.

It is not a de Polignac number, because 20278643 - 2⁶ = 20278579 is a prime.

It is a super-2 number, since 2×20278643² = 822446723842898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20278649) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 121346 + ... + 121512.

It is an arithmetic number, because the mean of its divisors is an integer number (846720).

Almost surely, 2^20278643 is an apocalyptic number.

20278643 is a deficient number, since it is larger than the sum of its proper divisors (6816397).

20278643 is a wasteful number, since it uses less digits than its factorization.

20278643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287.

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 20278643 is about 4503.1814309441. The cubic root of 20278643 is about 272.6965414295.

The spelling of 20278643 in words is "twenty million, two hundred seventy-eight thousand, six hundred forty-three".