1621531668 has 24 divisors (see below), whose sum is σ = 3982709920. Its totient is φ = 512062560.

The previous prime is 1621531651. The next prime is 1621531727. The reversal of 1621531668 is 8661351261.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3555763 + ... + 3556218.

Almost surely, 2^1621531668 is an apocalyptic number.

It is an amenable number.

1621531668 is an abundant number, since it is smaller than the sum of its proper divisors (2361178252).

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

1621531668 is a wasteful number, since it uses less digits than its factorization.

1621531668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7112007 (or 7112005 counting only the distinct ones).

The product of its digits is 51840, while the sum is 39.

The square root of 1621531668 is about 40268.2463983720. The cubic root of 1621531668 is about 1174.8303163449.

The spelling of 1621531668 in words is "one billion, six hundred twenty-one million, five hundred thirty-one thousand, six hundred sixty-eight".