23553781 has 2 divisors, whose sum is σ = 23553782. Its totient is φ = 23553780.

The previous prime is 23553779. The next prime is 23553797. The reversal of 23553781 is 18735532.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21771556 + 1782225 = 4666^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 23553781 - 2¹ = 23553779 is a prime.

It is a super-2 number, since 2×23553781² = 1109561198791922, which contains 22 as substring.

Together with 23553779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23553181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11776890 + 11776891.

It is an arithmetic number, because the mean of its divisors is an integer number (11776891).

Almost surely, 2^23553781 is an apocalyptic number.

It is an amenable number.

23553781 is a deficient number, since it is larger than the sum of its proper divisors (1).

23553781 is an equidigital number, since it uses as much as digits as its factorization.

23553781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 34.

The square root of 23553781 is about 4853.2237739466. The cubic root of 23553781 is about 286.6510548255.

The spelling of 23553781 in words is "twenty-three million, five hundred fifty-three thousand, seven hundred eighty-one".