161157821 has 8 divisors (see below), whose sum is σ = 175929600. Its totient is φ = 146406240.

The previous prime is 161157811. The next prime is 161157823. The reversal of 161157821 is 128751161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161157821 - 2¹⁰ = 161156797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161157823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15185 + ... + 23513.

It is an arithmetic number, because the mean of its divisors is an integer number (21991200).

Almost surely, 2^161157821 is an apocalyptic number.

161157821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161157821 is a deficient number, since it is larger than the sum of its proper divisors (14771779).

161157821 is a wasteful number, since it uses less digits than its factorization.

161157821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10099.

The product of its digits is 3360, while the sum is 32.

The square root of 161157821 is about 12694.7950357617. The cubic root of 161157821 is about 544.1898813162.

The spelling of 161157821 in words is "one hundred sixty-one million, one hundred fifty-seven thousand, eight hundred twenty-one".