65640215 has 8 divisors (see below), whose sum is σ = 78957888. Its totient is φ = 52385760.

The previous prime is 65640187. The next prime is 65640233. The reversal of 65640215 is 51204656.

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

It is not a de Polignac number, because 65640215 - 2⁶ = 65640151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13487 + ... + 17696.

It is an arithmetic number, because the mean of its divisors is an integer number (9869736).

Almost surely, 2^65640215 is an apocalyptic number.

65640215 is a deficient number, since it is larger than the sum of its proper divisors (13317673).

65640215 is a wasteful number, since it uses less digits than its factorization.

65640215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31609.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 65640215 is about 8101.8649087725. The cubic root of 65640215 is about 403.3883315632.

The spelling of 65640215 in words is "sixty-five million, six hundred forty thousand, two hundred fifteen".