1621444388 has 12 divisors (see below), whose sum is σ = 2838640140. Its totient is φ = 810404352.

The previous prime is 1621444369. The next prime is 1621444417. The reversal of 1621444388 is 8834441261.

It can be written as a sum of positive squares in 2 ways, for example, as 892336384 + 729108004 = 29872^2 + 27002^2 .

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, 67793 + ... + 88536.

It is an arithmetic number, because the mean of its divisors is an integer number (236553345).

Almost surely, 2^1621444388 is an apocalyptic number.

It is an amenable number.

1621444388 is a deficient number, since it is larger than the sum of its proper divisors (1217195752).

1621444388 is a wasteful number, since it uses less digits than its factorization.

1621444388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158926 (or 158924 counting only the distinct ones).

The product of its digits is 147456, while the sum is 41.

The square root of 1621444388 is about 40267.1626514707. The cubic root of 1621444388 is about 1174.8092372973.

The spelling of 1621444388 in words is "one billion, six hundred twenty-one million, four hundred forty-four thousand, three hundred eighty-eight".