56721378 has 16 divisors (see below), whose sum is σ = 129648960. Its totient is φ = 16206096.

The previous prime is 56721359. The next prime is 56721389. The reversal of 56721378 is 87312765.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 675213 + ... + 675296.

It is an arithmetic number, because the mean of its divisors is an integer number (8103060).

Almost surely, 2^56721378 is an apocalyptic number.

56721378 is an abundant number, since it is smaller than the sum of its proper divisors (72927582).

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

56721378 is a wasteful number, since it uses less digits than its factorization.

56721378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1350521.

The product of its digits is 70560, while the sum is 39.

The square root of 56721378 is about 7531.3596382061. The cubic root of 56721378 is about 384.2220260068. Note that the first 3 decimals are identical.

It can be divided in two parts, 567 and 21378, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 56721378 in words is "fifty-six million, seven hundred twenty-one thousand, three hundred seventy-eight".