20123649 has 24 divisors (see below), whose sum is σ = 35776832. Its totient is φ = 10614240.

The previous prime is 20123633. The next prime is 20123659. The reversal of 20123649 is 94632102.

20123649 is a `hidden beast` number, since 2 + 0 + 12 + 3 + 649 = 666.

It is a Cunningham number, because it is equal to 272³+1.

It is not a de Polignac number, because 20123649 - 2⁴ = 20123633 is a prime.

It is a super-2 number, since 2×20123649² = 809922498150402, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20123659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11467 + ... + 13104.

Almost surely, 2^20123649 is an apocalyptic number.

It is an amenable number.

20123649 is a deficient number, since it is larger than the sum of its proper divisors (15653183).

20123649 is a wasteful number, since it uses less digits than its factorization.

20123649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24597 (or 24594 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 20123649 is about 4485.9390321314. The cubic root of 20123649 is about 272.0000045055. Note that the first 5 decimals are identical.

The spelling of 20123649 in words is "twenty million, one hundred twenty-three thousand, six hundred forty-nine".