75401721 has 6 divisors (see below), whose sum is σ = 108913610. Its totient is φ = 50267808.

The previous prime is 75401717. The next prime is 75401737. The reversal of 75401721 is 12710457.

It can be written as a sum of positive squares in only one way, i.e., 73874025 + 1527696 = 8595^2 + 1236^2 .

It is not a de Polignac number, because 75401721 - 2² = 75401717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (75401741) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4188976 + ... + 4188993.

Almost surely, 2^75401721 is an apocalyptic number.

It is an amenable number.

75401721 is a deficient number, since it is larger than the sum of its proper divisors (33511889).

75401721 is a wasteful number, since it uses less digits than its factorization.

75401721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8377975 (or 8377972 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 75401721 is about 8683.4164359427. The cubic root of 75401721 is about 422.4679358975.

It can be divided in two parts, 7540 and 1721, that added together give a cube (9261 = 21³).

The spelling of 75401721 in words is "seventy-five million, four hundred one thousand, seven hundred twenty-one".