21146004553 has 2 divisors, whose sum is σ = 21146004554. Its totient is φ = 21146004552.

The previous prime is 21146004493. The next prime is 21146004587. The reversal of 21146004553 is 35540064112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19109468169 + 2036536384 = 138237^2 + 45128^2 .

It is a cyclic number.

It is not a de Polignac number, because 21146004553 - 2²¹ = 21143907401 is a prime.

It is not a weakly prime, because it can be changed into another prime (21146004653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10573002276 + 10573002277.

It is an arithmetic number, because the mean of its divisors is an integer number (10573002277).

Almost surely, 2^21146004553 is an apocalyptic number.

It is an amenable number.

21146004553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21146004553 is an equidigital number, since it uses as much as digits as its factorization.

21146004553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 31.

Adding to 21146004553 its reverse (35540064112), we get a palindrome (56686068665).

The spelling of 21146004553 in words is "twenty-one billion, one hundred forty-six million, four thousand, five hundred fifty-three".