1621678806 has 80 divisors (see below), whose sum is σ = 3993232320. Its totient is φ = 487807920.

The previous prime is 1621678801. The next prime is 1621678829. The reversal of 1621678806 is 6088761261.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621678801) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 244425 + ... + 250971.

It is an arithmetic number, because the mean of its divisors is an integer number (49915404).

Almost surely, 2^1621678806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621678806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1996616160).

1621678806 is an abundant number, since it is smaller than the sum of its proper divisors (2371553514).

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

1621678806 is a wasteful number, since it uses less digits than its factorization.

1621678806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6711 (or 6702 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 1621678806 is about 40270.0733299556. The cubic root of 1621678806 is about 1174.8658500234.

The spelling of 1621678806 in words is "one billion, six hundred twenty-one million, six hundred seventy-eight thousand, eight hundred six".