1057232721 has 4 divisors (see below), whose sum is σ = 1409643632. Its totient is φ = 704821812.

The previous prime is 1057232719. The next prime is 1057232753. The reversal of 1057232721 is 1272327501.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1057232721 - 2¹ = 1057232719 is a prime.

It is a super-2 number, since 2×1057232721² = 2235482052706127682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1057232791) 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, 176205451 + ... + 176205456.

It is an arithmetic number, because the mean of its divisors is an integer number (352410908).

Almost surely, 2^1057232721 is an apocalyptic number.

It is an amenable number.

1057232721 is a deficient number, since it is larger than the sum of its proper divisors (352410911).

1057232721 is an equidigital number, since it uses as much as digits as its factorization.

1057232721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352410910.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 1057232721 is about 32515.1152696711. The cubic root of 1057232721 is about 1018.7247683113.

The spelling of 1057232721 in words is "one billion, fifty-seven million, two hundred thirty-two thousand, seven hundred twenty-one".