1061721157 has 4 divisors (see below), whose sum is σ = 1213395616. Its totient is φ = 910046700.

The previous prime is 1061721151. The next prime is 1061721161. The reversal of 1061721157 is 7511271601.

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.

It is a cyclic number.

It is not a de Polignac number, because 1061721157 - 2⁷ = 1061721029 is a prime.

It is a super-2 number, since 2×1061721157² = 2254503630442837298, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1061721151) 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, 75837219 + ... + 75837232.

It is an arithmetic number, because the mean of its divisors is an integer number (303348904).

Almost surely, 2^1061721157 is an apocalyptic number.

It is an amenable number.

1061721157 is a deficient number, since it is larger than the sum of its proper divisors (151674459).

1061721157 is an equidigital number, since it uses as much as digits as its factorization.

1061721157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151674458.

The product of its (nonzero) digits is 2940, while the sum is 31.

The square root of 1061721157 is about 32584.0629295980. The cubic root of 1061721157 is about 1020.1643836692.

Adding to 1061721157 its reverse (7511271601), we get a palindrome (8572992758).

The spelling of 1061721157 in words is "one billion, sixty-one million, seven hundred twenty-one thousand, one hundred fifty-seven".