161407993 has 2 divisors, whose sum is σ = 161407994. Its totient is φ = 161407992.

The previous prime is 161407991. The next prime is 161408029. The reversal of 161407993 is 399704161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130804969 + 30603024 = 11437^2 + 5532^2 .

It is a cyclic number.

It is not a de Polignac number, because 161407993 - 2¹ = 161407991 is a prime.

Together with 161407991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (161407991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80703996 + 80703997.

It is an arithmetic number, because the mean of its divisors is an integer number (80703997).

Almost surely, 2^161407993 is an apocalyptic number.

It is an amenable number.

161407993 is a deficient number, since it is larger than the sum of its proper divisors (1).

161407993 is an equidigital number, since it uses as much as digits as its factorization.

161407993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 161407993 is about 12704.6445444176. The cubic root of 161407993 is about 544.4713252759.

The spelling of 161407993 in words is "one hundred sixty-one million, four hundred seven thousand, nine hundred ninety-three".