21546154309 has 2 divisors, whose sum is σ = 21546154310. Its totient is φ = 21546154308.

The previous prime is 21546154303. The next prime is 21546154411. The reversal of 21546154309 is 90345164512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21381750625 + 164403684 = 146225^2 + 12822^2 .

It is a cyclic number.

It is not a de Polignac number, because 21546154309 - 2²³ = 21537765701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21546154303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10773077154 + 10773077155.

It is an arithmetic number, because the mean of its divisors is an integer number (10773077155).

Almost surely, 2^21546154309 is an apocalyptic number.

It is an amenable number.

21546154309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21546154309 is an equidigital number, since it uses as much as digits as its factorization.

21546154309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 40.

The spelling of 21546154309 in words is "twenty-one billion, five hundred forty-six million, one hundred fifty-four thousand, three hundred nine".