1629621978 has 16 divisors (see below), whose sum is σ = 3272883840. Its totient is φ = 540934016.

The previous prime is 1629621953. The next prime is 1629621991. The reversal of 1629621978 is 8791269261.

It is a self number, because there is not a number n which added to its sum of digits gives 1629621978.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566775 + ... + 569642.

It is an arithmetic number, because the mean of its divisors is an integer number (204555240).

Almost surely, 2^1629621978 is an apocalyptic number.

1629621978 is an abundant number, since it is smaller than the sum of its proper divisors (1643261862).

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

1629621978 is a wasteful number, since it uses less digits than its factorization.

1629621978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136661.

The product of its digits is 653184, while the sum is 51.

The square root of 1629621978 is about 40368.5766159769. The cubic root of 1629621978 is about 1176.7809366493.

The spelling of 1629621978 in words is "one billion, six hundred twenty-nine million, six hundred twenty-one thousand, nine hundred seventy-eight".