268138971920 has 20 divisors (see below), whose sum is σ = 623423109900. Its totient is φ = 107255588736.

The previous prime is 268138971907. The next prime is 268138971929. The reversal of 268138971920 is 29179831862.

It can be written as a sum of positive squares in 2 ways, for example, as 38996770576 + 229142201344 = 197476^2 + 478688^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (268138971929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1675868495 + ... + 1675868654.

It is an arithmetic number, because the mean of its divisors is an integer number (31171155495).

Almost surely, 2^268138971920 is an apocalyptic number.

268138971920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

268138971920 is an abundant number, since it is smaller than the sum of its proper divisors (355284137980).

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

268138971920 is a wasteful number, since it uses less digits than its factorization.

268138971920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3351737162 (or 3351737156 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 56.

The spelling of 268138971920 in words is "two hundred sixty-eight billion, one hundred thirty-eight million, nine hundred seventy-one thousand, nine hundred twenty".