1621631826 has 48 divisors (see below), whose sum is σ = 3649245600. Its totient is φ = 539716608.

The previous prime is 1621631821. The next prime is 1621631827. The reversal of 1621631826 is 6281361261.

It is a happy number.

1621631826 is a `hidden beast` number, since 1 + 621 + 6 + 3 + 1 + 8 + 26 = 666.

It is not an unprimeable number, because it can be changed into a prime (1621631821) by changing a digit.

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, 371565 + ... + 375903.

It is an arithmetic number, because the mean of its divisors is an integer number (76025950).

Almost surely, 2^1621631826 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621631826, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1824622800).

1621631826 is an abundant number, since it is smaller than the sum of its proper divisors (2027613774).

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

1621631826 is an equidigital number, since it uses as much as digits as its factorization.

1621631826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5125 (or 5113 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 1621631826 is about 40269.4900141534. The cubic root of 1621631826 is about 1174.8545046344.

The spelling of 1621631826 in words is "one billion, six hundred twenty-one million, six hundred thirty-one thousand, eight hundred twenty-six".