20678440 has 24 divisors (see below), whose sum is σ = 46591290. Its totient is φ = 8259872.

The previous prime is 20678431. The next prime is 20678447. The reversal of 20678440 is 4487602.

It can be written as a sum of positive squares in only one way, i.e., 18610596 + 2067844 = 4314^2 + 1438^2 .

It is not an unprimeable number, because it can be changed into a prime (20678447) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28401 + ... + 29119.

Almost surely, 2^20678440 is an apocalyptic number.

20678440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20678440 is an abundant number, since it is smaller than the sum of its proper divisors (25912850).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20678440 is an frugal number, since it uses more digits than its factorization.

20678440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1449 (or 726 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 20678440 is about 4547.3552753221. The cubic root of 20678440 is about 274.4769783492.

The spelling of 20678440 in words is "twenty million, six hundred seventy-eight thousand, four hundred forty".