1621794720 has 384 divisors, whose sum is σ = 6364624896. Its totient is φ = 338006016.

The previous prime is 1621794719. The next prime is 1621794793. The reversal of 1621794720 is 274971261.

It is a super-2 number, since 2×1621794720² = 5260436227639756800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4673587 + ... + 4673933.

It is an arithmetic number, because the mean of its divisors is an integer number (16574544).

Almost surely, 2^1621794720 is an apocalyptic number.

1621794720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621794720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3182312448).

1621794720 is an abundant number, since it is smaller than the sum of its proper divisors (4742830176).

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

1621794720 is a wasteful number, since it uses less digits than its factorization.

1621794720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 484 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 39.

The square root of 1621794720 is about 40271.5125119482. The cubic root of 1621794720 is about 1174.8938416239.

The spelling of 1621794720 in words is "one billion, six hundred twenty-one million, seven hundred ninety-four thousand, seven hundred twenty".