161121761 has 2 divisors, whose sum is σ = 161121762. Its totient is φ = 161121760.

The previous prime is 161121707. The next prime is 161121799. The reversal of 161121761 is 167121161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108472225 + 52649536 = 10415^2 + 7256^2 .

It is a cyclic number.

It is not a de Polignac number, because 161121761 - 2¹⁴ = 161105377 is a prime.

It is a super-2 number, since 2×161121761² = 51920443735482242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161121761.

It is not a weakly prime, because it can be changed into another prime (161121661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80560880 + 80560881.

It is an arithmetic number, because the mean of its divisors is an integer number (80560881).

Almost surely, 2^161121761 is an apocalyptic number.

It is an amenable number.

161121761 is a deficient number, since it is larger than the sum of its proper divisors (1).

161121761 is an equidigital number, since it uses as much as digits as its factorization.

161121761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504, while the sum is 26.

The square root of 161121761 is about 12693.3746891833. The cubic root of 161121761 is about 544.1492897379.

The spelling of 161121761 in words is "one hundred sixty-one million, one hundred twenty-one thousand, seven hundred sixty-one".