1621663443 has 16 divisors (see below), whose sum is σ = 2418380800. Its totient is φ = 1073946600.

The previous prime is 1621663427. The next prime is 1621663451. The reversal of 1621663443 is 3443661261.

1621663443 is a `hidden beast` number, since 1 + 6 + 2 + 16 + 634 + 4 + 3 = 666.

It is not a de Polignac number, because 1621663443 - 2⁴ = 1621663427 is a prime.

It is a super-2 number, since 2×1621663443² = 5259584644725228498, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 1621663398 and 1621663407.

It is not an unprimeable number, because it can be changed into a prime (1621663943) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194803 + ... + 202956.

It is an arithmetic number, because the mean of its divisors is an integer number (151148800).

Almost surely, 2^1621663443 is an apocalyptic number.

1621663443 is a deficient number, since it is larger than the sum of its proper divisors (796717357).

1621663443 is a wasteful number, since it uses less digits than its factorization.

1621663443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397919 (or 397913 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 1621663443 is about 40269.8825799132. The cubic root of 1621663443 is about 1174.8621399749.

The spelling of 1621663443 in words is "one billion, six hundred twenty-one million, six hundred sixty-three thousand, four hundred forty-three".