12640651 has 4 divisors (see below), whose sum is σ = 12793032. Its totient is φ = 12488272.

The previous prime is 12640633. The next prime is 12640657. The reversal of 12640651 is 15604621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15604621 = 149 ⋅104729.

It is a cyclic number.

It is not a de Polignac number, because 12640651 - 2⁵ = 12640619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12640657) 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, 76066 + ... + 76231.

It is an arithmetic number, because the mean of its divisors is an integer number (3198258).

Almost surely, 2^12640651 is an apocalyptic number.

12640651 is a deficient number, since it is larger than the sum of its proper divisors (152381).

12640651 is an equidigital number, since it uses as much as digits as its factorization.

12640651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152380.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 12640651 is about 3555.3693197754. The cubic root of 12640651 is about 232.9466559284.

The spelling of 12640651 in words is "twelve million, six hundred forty thousand, six hundred fifty-one".