20778278 has 4 divisors (see below), whose sum is σ = 31167420. Its totient is φ = 10389138.

The previous prime is 20778253. The next prime is 20778283. The reversal of 20778278 is 87287702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87287702 = 2 ⋅43643851.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5194568 + ... + 5194571.

It is an arithmetic number, because the mean of its divisors is an integer number (7791855).

Almost surely, 2^20778278 is an apocalyptic number.

20778278 is a deficient number, since it is larger than the sum of its proper divisors (10389142).

20778278 is a wasteful number, since it uses less digits than its factorization.

20778278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10389141.

The product of its (nonzero) digits is 87808, while the sum is 41.

The square root of 20778278 is about 4558.3196465364. The cubic root of 20778278 is about 274.9180053068.

The spelling of 20778278 in words is "twenty million, seven hundred seventy-eight thousand, two hundred seventy-eight".