1620871978 has 8 divisors (see below), whose sum is σ = 2652336000. Its totient is φ = 736759980.

The previous prime is 1620871951. The next prime is 1620871979. The reversal of 1620871978 is 8791780261.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (1620871979) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 36837978 + ... + 36838021.

It is an arithmetic number, because the mean of its divisors is an integer number (331542000).

Almost surely, 2^1620871978 is an apocalyptic number.

1620871978 is a deficient number, since it is larger than the sum of its proper divisors (1031464022).

1620871978 is a wasteful number, since it uses less digits than its factorization.

1620871978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73676012.

The product of its (nonzero) digits is 338688, while the sum is 49.

The square root of 1620871978 is about 40260.0543715480. The cubic root of 1620871978 is about 1174.6709754469.

The spelling of 1620871978 in words is "one billion, six hundred twenty million, eight hundred seventy-one thousand, nine hundred seventy-eight".