1621649956 has 12 divisors (see below), whose sum is σ = 2935745820. Its totient is φ = 782865440.

The previous prime is 1621649947. The next prime is 1621650001. The reversal of 1621649956 is 6599461261.

It can be written as a sum of positive squares in 2 ways, for example, as 425596900 + 1196053056 = 20630^2 + 34584^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6989755 + ... + 6989986.

It is an arithmetic number, because the mean of its divisors is an integer number (244645485).

Almost surely, 2^1621649956 is an apocalyptic number.

It is an amenable number.

1621649956 is a deficient number, since it is larger than the sum of its proper divisors (1314095864).

1621649956 is a wasteful number, since it uses less digits than its factorization.

1621649956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13979774 (or 13979772 counting only the distinct ones).

The product of its digits is 699840, while the sum is 49.

The square root of 1621649956 is about 40269.7151219126. The cubic root of 1621649956 is about 1174.8588829469.

The spelling of 1621649956 in words is "one billion, six hundred twenty-one million, six hundred forty-nine thousand, nine hundred fifty-six".