1620221204 has 12 divisors (see below), whose sum is σ = 3240442464. Its totient is φ = 694380504.

The previous prime is 1620221173. The next prime is 1620221221. The reversal of 1620221204 is 4021220261.

It is a happy number.

1620221204 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28932494 + ... + 28932549.

It is an arithmetic number, because the mean of its divisors is an integer number (270036872).

Almost surely, 2^1620221204 is an apocalyptic number.

1620221204 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1620221204 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1620221204 is a wasteful number, since it uses less digits than its factorization.

1620221204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57865054 (or 57865052 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 1620221204 is about 40251.9714299809. The cubic root of 1620221204 is about 1174.5137457438.

Adding to 1620221204 its reverse (4021220261), we get a palindrome (5641441465).

The spelling of 1620221204 in words is "one billion, six hundred twenty million, two hundred twenty-one thousand, two hundred four".