1621799380 has 12 divisors (see below), whose sum is σ = 3405778740. Its totient is φ = 648719744.

The previous prime is 1621799363. The next prime is 1621799449. The reversal of 1621799380 is 839971261.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 648109764 + 973689616 = 25458^2 + 31204^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1621799380.

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, 40544965 + ... + 40545004.

It is an arithmetic number, because the mean of its divisors is an integer number (283814895).

Almost surely, 2^1621799380 is an apocalyptic number.

1621799380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621799380 is an abundant number, since it is smaller than the sum of its proper divisors (1783979360).

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

1621799380 is a wasteful number, since it uses less digits than its factorization.

1621799380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81089978 (or 81089976 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 1621799380 is about 40271.5703691823. The cubic root of 1621799380 is about 1174.8949669204.

The spelling of 1621799380 in words is "one billion, six hundred twenty-one million, seven hundred ninety-nine thousand, three hundred eighty".