53216781 has 8 divisors (see below), whose sum is σ = 71928000. Its totient is φ = 34991712.

The previous prime is 53216759. The next prime is 53216789. The reversal of 53216781 is 18761235.

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

It is not a de Polignac number, because 53216781 - 2⁹ = 53216269 is a prime.

It is a super-2 number, since 2×53216781² = 5664051560003922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53216789) 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, 121281 + ... + 121718.

It is an arithmetic number, because the mean of its divisors is an integer number (8991000).

Almost surely, 2^53216781 is an apocalyptic number.

It is an amenable number.

53216781 is a deficient number, since it is larger than the sum of its proper divisors (18711219).

53216781 is a wasteful number, since it uses less digits than its factorization.

53216781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243075.

The product of its digits is 10080, while the sum is 33.

The square root of 53216781 is about 7294.9832761974. The cubic root of 53216781 is about 376.1400117058.

The spelling of 53216781 in words is "fifty-three million, two hundred sixteen thousand, seven hundred eighty-one".