1621211999 has 8 divisors (see below), whose sum is σ = 1770048720. Its totient is φ = 1472617600.

The previous prime is 1621211989. The next prime is 1621212001. The reversal of 1621211999 is 9991121261.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1621211999 - 2¹⁶ = 1621146463 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621211939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46442 + ... + 73479.

It is an arithmetic number, because the mean of its divisors is an integer number (221256090).

Almost surely, 2^1621211999 is an apocalyptic number.

1621211999 is a deficient number, since it is larger than the sum of its proper divisors (148836721).

1621211999 is a wasteful number, since it uses less digits than its factorization.

1621211999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121161.

The product of its digits is 17496, while the sum is 41.

The square root of 1621211999 is about 40264.2769586143. The cubic root of 1621211999 is about 1174.7531091953.

The spelling of 1621211999 in words is "one billion, six hundred twenty-one million, two hundred eleven thousand, nine hundred ninety-nine".