1621245555 has 24 divisors (see below), whose sum is σ = 2875514928. Its totient is φ = 844554816.

The previous prime is 1621245541. The next prime is 1621245583. The reversal of 1621245555 is 5555421261.

1621245555 is a `hidden beast` number, since 1 + 62 + 1 + 2 + 45 + 555 = 666.

It is not a de Polignac number, because 1621245555 - 2⁶ = 1621245491 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 416992 + ... + 420861.

It is an arithmetic number, because the mean of its divisors is an integer number (119813122).

Almost surely, 2^1621245555 is an apocalyptic number.

1621245555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1621245555 is a deficient number, since it is larger than the sum of its proper divisors (1254269373).

1621245555 is a wasteful number, since it uses less digits than its factorization.

1621245555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837907 (or 837904 counting only the distinct ones).

The product of its digits is 60000, while the sum is 36.

The square root of 1621245555 is about 40264.6936533733. The cubic root of 1621245555 is about 1174.7612141899.

The spelling of 1621245555 in words is "one billion, six hundred twenty-one million, two hundred forty-five thousand, five hundred fifty-five".