20142778 has 4 divisors (see below), whose sum is σ = 30214170. Its totient is φ = 10071388.

The previous prime is 20142769. The next prime is 20142797. The reversal of 20142778 is 87724102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17363889 + 2778889 = 4167^2 + 1667^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5035693 + ... + 5035696.

Almost surely, 2^20142778 is an apocalyptic number.

20142778 is a deficient number, since it is larger than the sum of its proper divisors (10071392).

20142778 is a wasteful number, since it uses less digits than its factorization.

20142778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10071391.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 20142778 is about 4488.0706322428. The cubic root of 20142778 is about 272.0861625099.

The spelling of 20142778 in words is "twenty million, one hundred forty-two thousand, seven hundred seventy-eight".