16161821 has 8 divisors (see below), whose sum is σ = 17458560. Its totient is φ = 14872752.

The previous prime is 16161809. The next prime is 16161823. The reversal of 16161821 is 12816161.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16161821 is a prime.

It is a super-2 number, since 2×16161821² = 522408916072082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16161823) 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, 2936 + ... + 6398.

It is an arithmetic number, because the mean of its divisors is an integer number (2182320).

Almost surely, 2^16161821 is an apocalyptic number.

It is an amenable number.

16161821 is a deficient number, since it is larger than the sum of its proper divisors (1296739).

16161821 is a wasteful number, since it uses less digits than its factorization.

16161821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3835.

The product of its digits is 576, while the sum is 26.

The square root of 16161821 is about 4020.1767374084. The cubic root of 16161821 is about 252.8308690623.

Adding to 16161821 its reverse (12816161), we get a palindrome (28977982).

The spelling of 16161821 in words is "sixteen million, one hundred sixty-one thousand, eight hundred twenty-one".