16021638 has 20 divisors (see below), whose sum is σ = 35900700. Its totient is φ = 5340492.

The previous prime is 16021613. The next prime is 16021651. The reversal of 16021638 is 83612061.

16021638 is a `hidden beast` number, since 1 + 6 + 0 + 21 + 638 = 666.

16021638 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 49288 + ... + 49611.

It is an arithmetic number, because the mean of its divisors is an integer number (1795035).

Almost surely, 2^16021638 is an apocalyptic number.

16021638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

16021638 is an abundant number, since it is smaller than the sum of its proper divisors (19879062).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16021638 is an equidigital number, since it uses as much as digits as its factorization.

16021638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98913 (or 98904 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 16021638 is about 4002.7038361588. The cubic root of 16021638 is about 252.0977511929.

Adding to 16021638 its reverse (83612061), we get a palindrome (99633699).

It can be divided in two parts, 1602 and 1638, that added together give a triangular number (3240 = T₈₀).

The spelling of 16021638 in words is "sixteen million, twenty-one thousand, six hundred thirty-eight".