1621635872 has 12 divisors (see below), whose sum is σ = 3192595686. Its totient is φ = 810817920.

The previous prime is 1621635871. The next prime is 1621635919. The reversal of 1621635872 is 2785361261.

It can be written as a sum of positive squares in only one way, i.e., 1389500176 + 232135696 = 37276^2 + 15236^2 .

It is not an unprimeable number, because it can be changed into a prime (1621635871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25338029 + ... + 25338092.

Almost surely, 2^1621635872 is an apocalyptic number.

It is an amenable number.

1621635872 is a deficient number, since it is larger than the sum of its proper divisors (1570959814).

1621635872 is an equidigital number, since it uses as much as digits as its factorization.

1621635872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50676131 (or 50676123 counting only the distinct ones).

The product of its digits is 120960, while the sum is 41.

The square root of 1621635872 is about 40269.5402506659. The cubic root of 1621635872 is about 1174.8554817278.

The spelling of 1621635872 in words is "one billion, six hundred twenty-one million, six hundred thirty-five thousand, eight hundred seventy-two".