1621873220 has 24 divisors (see below), whose sum is σ = 3715564608. Its totient is φ = 589772000.

The previous prime is 1621873213. The next prime is 1621873229. The reversal of 1621873220 is 223781261.

It is not an unprimeable number, because it can be changed into a prime (1621873229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3685856 + ... + 3686295.

It is an arithmetic number, because the mean of its divisors is an integer number (154815192).

Almost surely, 2^1621873220 is an apocalyptic number.

1621873220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621873220 is an abundant number, since it is smaller than the sum of its proper divisors (2093691388).

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

1621873220 is a wasteful number, since it uses less digits than its factorization.

1621873220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7372171 (or 7372169 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 1621873220 is about 40272.4871345190. The cubic root of 1621873220 is about 1174.9127975121.

The spelling of 1621873220 in words is "one billion, six hundred twenty-one million, eight hundred seventy-three thousand, two hundred twenty".