21154372097 has 2 divisors, whose sum is σ = 21154372098. Its totient is φ = 21154372096.

The previous prime is 21154372091. The next prime is 21154372111. The reversal of 21154372097 is 79027345112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12716847361 + 8437524736 = 112769^2 + 91856^2 .

It is a cyclic number.

It is not a de Polignac number, because 21154372097 - 2⁶ = 21154372033 is a prime.

It is not a weakly prime, because it can be changed into another prime (21154372091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577186048 + 10577186049.

It is an arithmetic number, because the mean of its divisors is an integer number (10577186049).

Almost surely, 2^21154372097 is an apocalyptic number.

It is an amenable number.

21154372097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154372097 is an equidigital number, since it uses as much as digits as its factorization.

21154372097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105840, while the sum is 41.

The spelling of 21154372097 in words is "twenty-one billion, one hundred fifty-four million, three hundred seventy-two thousand, ninety-seven".