20729951 has 8 divisors (see below), whose sum is σ = 22647504. Its totient is φ = 18817920.

The previous prime is 20729939. The next prime is 20729981. The reversal of 20729951 is 15992702.

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

It is not a de Polignac number, because 20729951 - 2²² = 16535647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20729981) 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 7 ways as a sum of consecutive naturals, for example, 13541 + ... + 14993.

It is an arithmetic number, because the mean of its divisors is an integer number (2830938).

Almost surely, 2^20729951 is an apocalyptic number.

20729951 is a deficient number, since it is larger than the sum of its proper divisors (1917553).

20729951 is a wasteful number, since it uses less digits than its factorization.

20729951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2761.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 20729951 is about 4553.0155940871. The cubic root of 20729951 is about 274.7047011994.

The spelling of 20729951 in words is "twenty million, seven hundred twenty-nine thousand, nine hundred fifty-one".