6402021978 has 32 divisors (see below), whose sum is σ = 14418634752. Its totient is φ = 1877425200.

The previous prime is 6402021961. The next prime is 6402021979. The reversal of 6402021978 is 8791202046.

6402021978 is a modest number, since divided by 21978 gives 6402 as remainder.

It is not an unprimeable number, because it can be changed into a prime (6402021979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1562476 + ... + 1566567.

It is an arithmetic number, because the mean of its divisors is an integer number (450582336).

Almost surely, 2^6402021978 is an apocalyptic number.

6402021978 is an abundant number, since it is smaller than the sum of its proper divisors (8016612774).

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

6402021978 is a wasteful number, since it uses less digits than its factorization.

6402021978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3129090.

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 6402021978 is about 80012.6363645143. The cubic root of 6402021978 is about 1856.8310376600.

The spelling of 6402021978 in words is "six billion, four hundred two million, twenty-one thousand, nine hundred seventy-eight".