1621554428 has 24 divisors (see below), whose sum is σ = 3130547280. Its totient is φ = 730154880.

The previous prime is 1621554427. The next prime is 1621554433. The reversal of 1621554428 is 8244551261.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1621554391 and 1621554400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621554427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 378158 + ... + 382421.

It is an arithmetic number, because the mean of its divisors is an integer number (130439470).

Almost surely, 2^1621554428 is an apocalyptic number.

It is an amenable number.

1621554428 is a deficient number, since it is larger than the sum of its proper divisors (1508992852).

1621554428 is a wasteful number, since it uses less digits than its factorization.

1621554428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760637 (or 760635 counting only the distinct ones).

The product of its digits is 76800, while the sum is 38.

The square root of 1621554428 is about 40268.5290021873. The cubic root of 1621554428 is about 1174.8358130025.

The spelling of 1621554428 in words is "one billion, six hundred twenty-one million, five hundred fifty-four thousand, four hundred twenty-eight".