15661650001 has 2 divisors, whose sum is σ = 15661650002. Its totient is φ = 15661650000.

The previous prime is 15661649987. The next prime is 15661650077. The reversal of 15661650001 is 10005616651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13242485776 + 2419164225 = 115076^2 + 49185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15661650001 is a prime.

It is not a weakly prime, because it can be changed into another prime (15661651001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7830825000 + 7830825001.

It is an arithmetic number, because the mean of its divisors is an integer number (7830825001).

Almost surely, 2^15661650001 is an apocalyptic number.

It is an amenable number.

15661650001 is a deficient number, since it is larger than the sum of its proper divisors (1).

15661650001 is an equidigital number, since it uses as much as digits as its factorization.

15661650001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 31.

The spelling of 15661650001 in words is "fifteen billion, six hundred sixty-one million, six hundred fifty thousand, one".