689540251 has 4 divisors (see below), whose sum is σ = 708176512. Its totient is φ = 670903992.

The previous prime is 689540249. The next prime is 689540273. The reversal of 689540251 is 152045986.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 152045986 = 2 ⋅76022993.

It is a cyclic number.

It is not a de Polignac number, because 689540251 - 2¹ = 689540249 is a prime.

It is a super-3 number, since 3×689540251³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689540051) 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, 9318075 + ... + 9318148.

It is an arithmetic number, because the mean of its divisors is an integer number (177044128).

Almost surely, 2^689540251 is an apocalyptic number.

689540251 is a deficient number, since it is larger than the sum of its proper divisors (18636261).

689540251 is a wasteful number, since it uses less digits than its factorization.

689540251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18636260.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 689540251 is about 26259.0984422543. The cubic root of 689540251 is about 883.4592878737.

The spelling of 689540251 in words is "six hundred eighty-nine million, five hundred forty thousand, two hundred fifty-one".