20516749 has 4 divisors (see below), whose sum is σ = 22381920. Its totient is φ = 18651580.

The previous prime is 20516737. The next prime is 20516753. The reversal of 20516749 is 94761502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20516749 - 2²³ = 12128141 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20516149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 932569 + ... + 932590.

It is an arithmetic number, because the mean of its divisors is an integer number (5595480).

Almost surely, 2^20516749 is an apocalyptic number.

It is an amenable number.

20516749 is a deficient number, since it is larger than the sum of its proper divisors (1865171).

20516749 is a wasteful number, since it uses less digits than its factorization.

20516749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865170.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 20516749 is about 4529.5418090575. The cubic root of 20516749 is about 273.7596992734.

The spelling of 20516749 in words is "twenty million, five hundred sixteen thousand, seven hundred forty-nine".