65661511651 has 4 divisors (see below), whose sum is σ = 65685400000. Its totient is φ = 65637623304.

The previous prime is 65661511631. The next prime is 65661511681. The reversal of 65661511651 is 15611516656.

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

It is a cyclic number.

It is not a de Polignac number, because 65661511651 - 2²³ = 65653123043 is a prime.

It is a super-2 number, since 2×65661511651² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65661511598 and 65661511607.

It is not an unprimeable number, because it can be changed into a prime (65661511621) 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, 11940051 + ... + 11945548.

It is an arithmetic number, because the mean of its divisors is an integer number (16421350000).

Almost surely, 2^65661511651 is an apocalyptic number.

65661511651 is a deficient number, since it is larger than the sum of its proper divisors (23888349).

65661511651 is a wasteful number, since it uses less digits than its factorization.

65661511651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23888348.

The product of its digits is 162000, while the sum is 43.

The spelling of 65661511651 in words is "sixty-five billion, six hundred sixty-one million, five hundred eleven thousand, six hundred fifty-one".