1621428016 has 40 divisors (see below), whose sum is σ = 3392404400. Its totient is φ = 746309376.

The previous prime is 1621427981. The next prime is 1621428037. The reversal of 1621428016 is 6108241261.

It is a super-2 number, since 2×1621428016² = 5258057622139392512, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67135 + ... + 88033.

It is an arithmetic number, because the mean of its divisors is an integer number (84810110).

Almost surely, 2^1621428016 is an apocalyptic number.

1621428016 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621428016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1696202200).

1621428016 is an abundant number, since it is smaller than the sum of its proper divisors (1770976384).

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

1621428016 is a wasteful number, since it uses less digits than its factorization.

1621428016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21293 (or 21287 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 1621428016 is about 40266.9593587596. The cubic root of 1621428016 is about 1174.8052832010.

Adding to 1621428016 its reverse (6108241261), we get a palindrome (7729669277).

The spelling of 1621428016 in words is "one billion, six hundred twenty-one million, four hundred twenty-eight thousand, sixteen".