65720557 has 8 divisors (see below), whose sum is σ = 75525632. Its totient is φ = 56019600.

The previous prime is 65720549. The next prime is 65720587. The reversal of 65720557 is 75502756.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65720557 - 2³ = 65720549 is a prime.

It is a super-2 number, since 2×65720557² = 8638383224780498, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65720587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24669 + ... + 27202.

It is an arithmetic number, because the mean of its divisors is an integer number (9440704).

Almost surely, 2^65720557 is an apocalyptic number.

It is an amenable number.

65720557 is a deficient number, since it is larger than the sum of its proper divisors (9805075).

65720557 is a wasteful number, since it uses less digits than its factorization.

65720557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52059.

The product of its (nonzero) digits is 73500, while the sum is 37.

The square root of 65720557 is about 8106.8216336614. The cubic root of 65720557 is about 403.5528435762.

The spelling of 65720557 in words is "sixty-five million, seven hundred twenty thousand, five hundred fifty-seven".