16121301661 has 2 divisors, whose sum is σ = 16121301662. Its totient is φ = 16121301660.

The previous prime is 16121301653. The next prime is 16121301667. The reversal of 16121301661 is 16610312161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15921644761 + 199656900 = 126181^2 + 14130^2 .

It is a cyclic number.

It is not a de Polignac number, because 16121301661 - 2³ = 16121301653 is a prime.

It is a super-2 number, since 2×16121301661² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16121301667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8060650830 + 8060650831.

It is an arithmetic number, because the mean of its divisors is an integer number (8060650831).

Almost surely, 2^16121301661 is an apocalyptic number.

It is an amenable number.

16121301661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16121301661 is an equidigital number, since it uses as much as digits as its factorization.

16121301661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 28.

The spelling of 16121301661 in words is "sixteen billion, one hundred twenty-one million, three hundred one thousand, six hundred sixty-one".