16861538 has 4 divisors (see below), whose sum is σ = 25292310. Its totient is φ = 8430768.

The previous prime is 16861519. The next prime is 16861541. The reversal of 16861538 is 83516861.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83516861 = 3539 ⋅23599.

It can be written as a sum of positive squares in only one way, i.e., 16216729 + 644809 = 4027^2 + 803^2 .

It is a super-2 number, since 2×16861538² = 568622927450888, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4215383 + ... + 4215386.

Almost surely, 2^16861538 is an apocalyptic number.

16861538 is a deficient number, since it is larger than the sum of its proper divisors (8430772).

16861538 is an equidigital number, since it uses as much as digits as its factorization.

16861538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8430771.

The product of its digits is 34560, while the sum is 38.

The square root of 16861538 is about 4106.2803119125. The cubic root of 16861538 is about 256.4281673490.

The spelling of 16861538 in words is "sixteen million, eight hundred sixty-one thousand, five hundred thirty-eight".