65816951381 has 4 divisors (see below), whose sum is σ = 65870159532. Its totient is φ = 65763743232.

The previous prime is 65816951357. The next prime is 65816951399. The reversal of 65816951381 is 18315961856.

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 47552780356 + 18264171025 = 218066^2 + 135145^2 .

It is a cyclic number.

It is not a de Polignac number, because 65816951381 - 2¹⁰ = 65816950357 is a prime.

It is a super-2 number, since 2×65816951381² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65816951581) 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, 26602220 + ... + 26604693.

It is an arithmetic number, because the mean of its divisors is an integer number (16467539883).

Almost surely, 2^65816951381 is an apocalyptic number.

It is an amenable number.

65816951381 is a deficient number, since it is larger than the sum of its proper divisors (53208151).

65816951381 is a wasteful number, since it uses less digits than its factorization.

65816951381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53208150.

The product of its digits is 1555200, while the sum is 53.

The spelling of 65816951381 in words is "sixty-five billion, eight hundred sixteen million, nine hundred fifty-one thousand, three hundred eighty-one".