1621245556 has 36 divisors (see below), whose sum is σ = 3354522276. Its totient is φ = 683424000.

The previous prime is 1621245541. The next prime is 1621245583. The reversal of 1621245556 is 6555421261.

It can be written as a sum of positive squares in 2 ways, for example, as 223981156 + 1397264400 = 14966^2 + 37380^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55845 + ... + 79756.

Almost surely, 2^1621245556 is an apocalyptic number.

It is an amenable number.

1621245556 is an abundant number, since it is smaller than the sum of its proper divisors (1733276720).

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

1621245556 is a wasteful number, since it uses less digits than its factorization.

1621245556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135680 (or 135671 counting only the distinct ones).

The product of its digits is 72000, while the sum is 37.

The square root of 1621245556 is about 40264.6936657911. The cubic root of 1621245556 is about 1174.7612144314.

The spelling of 1621245556 in words is "one billion, six hundred twenty-one million, two hundred forty-five thousand, five hundred fifty-six".