20553381 has 6 divisors (see below), whose sum is σ = 29688230. Its totient is φ = 13702248.

The previous prime is 20553361. The next prime is 20553433. The reversal of 20553381 is 18335502.

It can be written as a sum of positive squares in only one way, i.e., 19660356 + 893025 = 4434^2 + 945^2 .

It is not a de Polignac number, because 20553381 - 2¹⁷ = 20422309 is a prime.

It is a super-2 number, since 2×20553381² = 844882941062322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20553301) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1141846 + ... + 1141863.

Almost surely, 2^20553381 is an apocalyptic number.

It is an amenable number.

20553381 is a deficient number, since it is larger than the sum of its proper divisors (9134849).

20553381 is a wasteful number, since it uses less digits than its factorization.

20553381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2283715 (or 2283712 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 20553381 is about 4533.5836818129. The cubic root of 20553381 is about 273.9225321338.

Adding to 20553381 its reverse (18335502), we get a palindrome (38888883).

The spelling of 20553381 in words is "twenty million, five hundred fifty-three thousand, three hundred eighty-one".