20551385 has 8 divisors (see below), whose sum is σ = 26112456. Its totient is φ = 15473920.

The previous prime is 20551367. The next prime is 20551387. The reversal of 20551385 is 58315502.

It can be written as a sum of positive squares in 4 ways, for example, as 10137856 + 10413529 = 3184^2 + 3227^2 .

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

It is not a de Polignac number, because 20551385 - 2⁸ = 20551129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20551387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120806 + ... + 120975.

It is an arithmetic number, because the mean of its divisors is an integer number (3264057).

Almost surely, 2^20551385 is an apocalyptic number.

It is an amenable number.

20551385 is a deficient number, since it is larger than the sum of its proper divisors (5561071).

20551385 is a wasteful number, since it uses less digits than its factorization.

20551385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241803.

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 20551385 is about 4533.3635415660. The cubic root of 20551385 is about 273.9136647026.

Adding to 20551385 its reverse (58315502), we get a palindrome (78866887).

The spelling of 20551385 in words is "twenty million, five hundred fifty-one thousand, three hundred eighty-five".