661073257 has 4 divisors (see below), whose sum is σ = 711925060. Its totient is φ = 610221456.

The previous prime is 661073219. The next prime is 661073263. The reversal of 661073257 is 752370166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 297942121 + 363131136 = 17261^2 + 19056^2 .

It is not a de Polignac number, because 661073257 - 2⁷ = 661073129 is a prime.

It is a super-2 number, since 2×661073257² = 874035702241176098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661073207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25425882 + ... + 25425907.

It is an arithmetic number, because the mean of its divisors is an integer number (177981265).

Almost surely, 2^661073257 is an apocalyptic number.

It is an amenable number.

661073257 is a deficient number, since it is larger than the sum of its proper divisors (50851803).

661073257 is a wasteful number, since it uses less digits than its factorization.

661073257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50851802.

The product of its (nonzero) digits is 52920, while the sum is 37.

The square root of 661073257 is about 25711.3449084252. The cubic root of 661073257 is about 871.1304532401.

The spelling of 661073257 in words is "six hundred sixty-one million, seventy-three thousand, two hundred fifty-seven".