20401921 has 8 divisors (see below), whose sum is σ = 21907584. Its totient is φ = 18930240.

The previous prime is 20401919. The next prime is 20401933. The reversal of 20401921 is 12910402.

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 20401921 - 2¹ = 20401919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20401951) 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, 7245 + ... + 9658.

It is an arithmetic number, because the mean of its divisors is an integer number (2738448).

Almost surely, 2^20401921 is an apocalyptic number.

It is an amenable number.

20401921 is a deficient number, since it is larger than the sum of its proper divisors (1505663).

20401921 is a wasteful number, since it uses less digits than its factorization.

20401921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16991.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20401921 is about 4516.8485695228. The cubic root of 20401921 is about 273.2480180227.

The spelling of 20401921 in words is "twenty million, four hundred one thousand, nine hundred twenty-one".