20400078 has 16 divisors (see below), whose sum is σ = 40844880. Its totient is φ = 6792576.

The previous prime is 20400059. The next prime is 20400089. The reversal of 20400078 is 87000402.

It is a happy number.

20400078 is a nontrivial binomial coefficient, being equal to C(6388, 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8518 + ... + 10646.

It is an arithmetic number, because the mean of its divisors is an integer number (2552805).

Almost surely, 2^20400078 is an apocalyptic number.

20400078 is the 6387-th triangular number and also the 3194-th hexagonal number.

20400078 is an abundant number, since it is smaller than the sum of its proper divisors (20444802).

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

20400078 is a wasteful number, since it uses less digits than its factorization.

20400078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3731.

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 20400078 is about 4516.6445509914. The cubic root of 20400078 is about 273.2397898554.

The spelling of 20400078 in words is "twenty million, four hundred thousand, seventy-eight".