1621004320 has 48 divisors (see below), whose sum is σ = 4124214360. Its totient is φ = 598523904.

The previous prime is 1621004309. The next prime is 1621004321. The reversal of 1621004320 is 234001261.

It can be written as a sum of positive squares in 4 ways, for example, as 1034008336 + 586995984 = 32156^2 + 24228^2 .

It is not an unprimeable number, because it can be changed into a prime (1621004321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 387585 + ... + 391744.

Almost surely, 2^1621004320 is an apocalyptic number.

1621004320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621004320 is an abundant number, since it is smaller than the sum of its proper divisors (2503210040).

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

1621004320 is a wasteful number, since it uses less digits than its factorization.

1621004320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779357 (or 779349 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 1621004320 is about 40261.6979274347. The cubic root of 1621004320 is about 1174.7029446745.

Adding to 1621004320 its reverse (234001261), we get a palindrome (1855005581).

The spelling of 1621004320 in words is "one billion, six hundred twenty-one million, four thousand, three hundred twenty".