1621128964 has 72 divisors (see below), whose sum is σ = 3650507840. Its totient is φ = 613369152.

The previous prime is 1621128947. The next prime is 1621128983. The reversal of 1621128964 is 4698211261.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 188347 + ... + 196765.

Almost surely, 2^1621128964 is an apocalyptic number.

1621128964 is a gapful number since it is divisible by the number (14) 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 1621128964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1825253920).

1621128964 is an abundant number, since it is smaller than the sum of its proper divisors (2029378876).

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

1621128964 is a wasteful number, since it uses less digits than its factorization.

1621128964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8489 (or 8464 counting only the distinct ones).

The product of its digits is 41472, while the sum is 40.

The square root of 1621128964 is about 40263.2458204750. The cubic root of 1621128964 is about 1174.7330527417.

The spelling of 1621128964 in words is "one billion, six hundred twenty-one million, one hundred twenty-eight thousand, nine hundred sixty-four".