1621511616 has 56 divisors (see below), whose sum is σ = 4324096000. Its totient is φ = 536239872.

The previous prime is 1621511611. The next prime is 1621511651. The reversal of 1621511616 is 6161151261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621511611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8866 + ... + 57633.

It is an arithmetic number, because the mean of its divisors is an integer number (77216000).

Almost surely, 2^1621511616 is an apocalyptic number.

1621511616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1621511616 is an abundant number, since it is smaller than the sum of its proper divisors (2702584384).

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

1621511616 is a wasteful number, since it uses less digits than its factorization.

1621511616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66641 (or 66631 counting only the distinct ones).

The product of its digits is 2160, while the sum is 30.

The square root of 1621511616 is about 40267.9974173040. The cubic root of 1621511616 is about 1174.8254736407.

Adding to 1621511616 its reverse (6161151261), we get a palindrome (7782662877).

The spelling of 1621511616 in words is "one billion, six hundred twenty-one million, five hundred eleven thousand, six hundred sixteen".