16156421 has 4 divisors (see below), whose sum is σ = 16165152. Its totient is φ = 16147692.

The previous prime is 16156379. The next prime is 16156423. The reversal of 16156421 is 12465161.

16156421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12465161 = 199 ⋅62639.

It is a cyclic number.

It is not a de Polignac number, because 16156421 - 2¹⁰ = 16155397 is a prime.

It is a super-2 number, since 2×16156421² = 522059879058482, 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 (16156423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 371 + ... + 5696.

It is an arithmetic number, because the mean of its divisors is an integer number (4041288).

Almost surely, 2^16156421 is an apocalyptic number.

It is an amenable number.

16156421 is a deficient number, since it is larger than the sum of its proper divisors (8731).

16156421 is an equidigital number, since it uses as much as digits as its factorization.

16156421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8730.

The product of its digits is 1440, while the sum is 26.

The square root of 16156421 is about 4019.5050690352. The cubic root of 16156421 is about 252.8027072445.

The spelling of 16156421 in words is "sixteen million, one hundred fifty-six thousand, four hundred twenty-one".