20778771 has 8 divisors (see below), whose sum is σ = 29836240. Its totient is φ = 12786912.

The previous prime is 20778767. The next prime is 20778781. The reversal of 20778771 is 17787702.

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

It is not a de Polignac number, because 20778771 - 2² = 20778767 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 532789 = 20778771 / (2 + 0 + 7 + 7 + 8 + 7 + 7 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20778721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266356 + ... + 266433.

It is an arithmetic number, because the mean of its divisors is an integer number (3729530).

Almost surely, 2^20778771 is an apocalyptic number.

20778771 is a deficient number, since it is larger than the sum of its proper divisors (9057469).

20778771 is a wasteful number, since it uses less digits than its factorization.

20778771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532805.

The product of its (nonzero) digits is 38416, while the sum is 39.

The square root of 20778771 is about 4558.3737231605. The cubic root of 20778771 is about 274.9201795887.

The spelling of 20778771 in words is "twenty million, seven hundred seventy-eight thousand, seven hundred seventy-one".