1157721 has 4 divisors (see below), whose sum is σ = 1543632. Its totient is φ = 771812.

The previous prime is 1157713. The next prime is 1157729. The reversal of 1157721 is 1277511.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1277511 = 3 ⋅425837.

It is an interprime number because it is at equal distance from previous prime (1157713) and next prime (1157729).

It is a cyclic number.

It is not a de Polignac number, because 1157721 - 2³ = 1157713 is a prime.

It is a D-number.

It is a junction number, because it is equal to n+sod(n) for n = 1157691 and 1157700.

It is not an unprimeable number, because it can be changed into a prime (1157729) 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, 192951 + ... + 192956.

It is an arithmetic number, because the mean of its divisors is an integer number (385908).

2^1157721 is an apocalyptic number.

It is an amenable number.

1157721 is a deficient number, since it is larger than the sum of its proper divisors (385911).

1157721 is an equidigital number, since it uses as much as digits as its factorization.

1157721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385910.

The product of its digits is 490, while the sum is 24.

The square root of 1157721 is about 1075.9744420756. The cubic root of 1157721 is about 105.0029024141.

The spelling of 1157721 in words is "one million, one hundred fifty-seven thousand, seven hundred twenty-one".