20553387 has 4 divisors (see below), whose sum is σ = 27404520. Its totient is φ = 13702256.

The previous prime is 20553361. The next prime is 20553433. The reversal of 20553387 is 78335502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20553387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20553287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3425562 + ... + 3425567.

It is an arithmetic number, because the mean of its divisors is an integer number (6851130).

Almost surely, 2^20553387 is an apocalyptic number.

20553387 is a deficient number, since it is larger than the sum of its proper divisors (6851133).

20553387 is an equidigital number, since it uses as much as digits as its factorization.

20553387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6851132.

The product of its (nonzero) digits is 25200, while the sum is 33.

The square root of 20553387 is about 4533.5843435410. The cubic root of 20553387 is about 273.9225587885.

Adding to 20553387 its reverse (78335502), we get a palindrome (98888889).

The spelling of 20553387 in words is "twenty million, five hundred fifty-three thousand, three hundred eighty-seven".