161021954 has 4 divisors (see below), whose sum is σ = 241532934. Its totient is φ = 80510976.

The previous prime is 161021947. The next prime is 161021957. The reversal of 161021954 is 459120161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 155625625 + 5396329 = 12475^2 + 2323^2 .

It is not an unprimeable number, because it can be changed into a prime (161021957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40255487 + ... + 40255490.

Almost surely, 2^161021954 is an apocalyptic number.

161021954 is a deficient number, since it is larger than the sum of its proper divisors (80510980).

161021954 is an equidigital number, since it uses as much as digits as its factorization.

161021954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80510979.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 161021954 is about 12689.4426197528. The cubic root of 161021954 is about 544.0369086298.

The spelling of 161021954 in words is "one hundred sixty-one million, twenty-one thousand, nine hundred fifty-four".