23151978821 has 2 divisors, whose sum is σ = 23151978822. Its totient is φ = 23151978820.

The previous prime is 23151978799. The next prime is 23151978869. The reversal of 23151978821 is 12887915132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19186128196 + 3965850625 = 138514^2 + 62975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23151978821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23151908821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11575989410 + 11575989411.

It is an arithmetic number, because the mean of its divisors is an integer number (11575989411).

Almost surely, 2^23151978821 is an apocalyptic number.

It is an amenable number.

23151978821 is a deficient number, since it is larger than the sum of its proper divisors (1).

23151978821 is an equidigital number, since it uses as much as digits as its factorization.

23151978821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 47.

The spelling of 23151978821 in words is "twenty-three billion, one hundred fifty-one million, nine hundred seventy-eight thousand, eight hundred twenty-one".