16400073661 has 2 divisors, whose sum is σ = 16400073662. Its totient is φ = 16400073660.

The previous prime is 16400073643. The next prime is 16400073671. The reversal of 16400073661 is 16637000461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15458197561 + 941876100 = 124331^2 + 30690^2 .

It is a cyclic number.

It is not a de Polignac number, because 16400073661 - 2⁹ = 16400073149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16400073631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8200036830 + 8200036831.

It is an arithmetic number, because the mean of its divisors is an integer number (8200036831).

Almost surely, 2^16400073661 is an apocalyptic number.

It is an amenable number.

16400073661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16400073661 is an equidigital number, since it uses as much as digits as its factorization.

16400073661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 34.

The spelling of 16400073661 in words is "sixteen billion, four hundred million, seventy-three thousand, six hundred sixty-one".