20734721 has 4 divisors (see below), whose sum is σ = 23696832. Its totient is φ = 17772612.

The previous prime is 20734717. The next prime is 20734733. The reversal of 20734721 is 12743702.

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 20734721 - 2² = 20734717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20734771) 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, 1481045 + ... + 1481058.

It is an arithmetic number, because the mean of its divisors is an integer number (5924208).

Almost surely, 2^20734721 is an apocalyptic number.

It is an amenable number.

20734721 is a deficient number, since it is larger than the sum of its proper divisors (2962111).

20734721 is an equidigital number, since it uses as much as digits as its factorization.

20734721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2962110.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 20734721 is about 4553.5393926044. The cubic root of 20734721 is about 274.7257696032.

The spelling of 20734721 in words is "twenty million, seven hundred thirty-four thousand, seven hundred twenty-one".