1621225515 has 64 divisors (see below), whose sum is σ = 3257856000. Its totient is φ = 684093312.

The previous prime is 1621225511. The next prime is 1621225579. The reversal of 1621225515 is 5155221261.

It is not a de Polignac number, because 1621225515 - 2² = 1621225511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1621225511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 54766 + ... + 79004.

It is an arithmetic number, because the mean of its divisors is an integer number (50904000).

Almost surely, 2^1621225515 is an apocalyptic number.

1621225515 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1621225515 is an abundant number, since it is smaller than the sum of its proper divisors (1636630485).

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

1621225515 is a wasteful number, since it uses less digits than its factorization.

1621225515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24281 (or 24267 counting only the distinct ones).

The product of its digits is 6000, while the sum is 30.

The square root of 1621225515 is about 40264.4447993512. Note that the first 3 decimals coincide. The cubic root of 1621225515 is about 1174.7563738144.

Adding to 1621225515 its reverse (5155221261), we get a palindrome (6776446776).

The spelling of 1621225515 in words is "one billion, six hundred twenty-one million, two hundred twenty-five thousand, five hundred fifteen".