140521561 has 4 divisors (see below), whose sum is σ = 141885952. Its totient is φ = 139157172.

The previous prime is 140521547. The next prime is 140521571. The reversal of 140521561 is 165125041.

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: 165125041 = 421 ⋅392221.

It is a cyclic number.

It is not a de Polignac number, because 140521561 - 2⁹ = 140521049 is a prime.

It is a super-3 number, since 3×140521561³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (140521571) 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, 682041 + ... + 682246.

It is an arithmetic number, because the mean of its divisors is an integer number (35471488).

Almost surely, 2^140521561 is an apocalyptic number.

It is an amenable number.

140521561 is a deficient number, since it is larger than the sum of its proper divisors (1364391).

140521561 is a wasteful number, since it uses less digits than its factorization.

140521561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1364390.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 140521561 is about 11854.1790521318. The cubic root of 140521561 is about 519.8934212045.

The spelling of 140521561 in words is "one hundred forty million, five hundred twenty-one thousand, five hundred sixty-one".