20778402 has 8 divisors (see below), whose sum is σ = 41556816. Its totient is φ = 6926132.

The previous prime is 20778391. The next prime is 20778449. The reversal of 20778402 is 20487702.

It is a sphenic number, since it is the product of 3 distinct primes.

20778402 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 20778402.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1731528 + ... + 1731539.

It is an arithmetic number, because the mean of its divisors is an integer number (5194602).

Almost surely, 2^20778402 is an apocalyptic number.

20778402 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20778402 is a wasteful number, since it uses less digits than its factorization.

20778402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3463072.

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 20778402 is about 4558.3332480195. Note that the first 3 decimals coincide. The cubic root of 20778402 is about 274.9185521882.

The spelling of 20778402 in words is "twenty million, seven hundred seventy-eight thousand, four hundred two".