20721029 has 8 divisors (see below), whose sum is σ = 24069888. Its totient is φ = 17469360.

The previous prime is 20721013. The next prime is 20721037. The reversal of 20721029 is 92012702.

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

It is a cyclic number.

It is not a de Polignac number, because 20721029 - 2⁴ = 20721013 is a prime.

It is a super-2 number, since 2×20721029² = 858722085637682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20720995 and 20721013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20721089) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23837 + ... + 24690.

It is an arithmetic number, because the mean of its divisors is an integer number (3008736).

Almost surely, 2^20721029 is an apocalyptic number.

It is an amenable number.

20721029 is a deficient number, since it is larger than the sum of its proper divisors (3348859).

20721029 is an equidigital number, since it uses as much as digits as its factorization.

20721029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48595.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 20721029 is about 4552.0356984540. The cubic root of 20721029 is about 274.6652853312.

The spelling of 20721029 in words is "twenty million, seven hundred twenty-one thousand, twenty-nine".