126721440 has 72 divisors (see below), whose sum is σ = 432441828. Its totient is φ = 33792000.

The previous prime is 126721403. The next prime is 126721453. The reversal of 126721440 is 44127621.

It can be written as a sum of positive squares in 2 ways, for example, as 106254864 + 20466576 = 10308^2 + 4524^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42561 + ... + 45440.

Almost surely, 2^126721440 is an apocalyptic number.

126721440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

126721440 is an abundant number, since it is smaller than the sum of its proper divisors (305720388).

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

126721440 is a wasteful number, since it uses less digits than its factorization.

126721440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88022 (or 88011 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 126721440 is about 11257.0617836094. The cubic root of 126721440 is about 502.2847968371.

The spelling of 126721440 in words is "one hundred twenty-six million, seven hundred twenty-one thousand, four hundred forty".