20738921 has 4 divisors (see below), whose sum is σ = 23701632. Its totient is φ = 17776212.

The previous prime is 20738917. The next prime is 20738933. The reversal of 20738921 is 12983702.

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 20738921 - 2² = 20738917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20738951) 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, 1481345 + ... + 1481358.

It is an arithmetic number, because the mean of its divisors is an integer number (5925408).

Almost surely, 2^20738921 is an apocalyptic number.

It is an amenable number.

20738921 is a deficient number, since it is larger than the sum of its proper divisors (2962711).

20738921 is an equidigital number, since it uses as much as digits as its factorization.

20738921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2962710.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 20738921 is about 4554.0005489679. Note that the first 3 decimals coincide. The cubic root of 20738921 is about 274.7443177240.

The spelling of 20738921 in words is "twenty million, seven hundred thirty-eight thousand, nine hundred twenty-one".