20401999 has 8 divisors (see below), whose sum is σ = 21407360. Its totient is φ = 19418400.

The previous prime is 20401973. The next prime is 20402009. The reversal of 20401999 is 99910402.

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

It is not a de Polignac number, because 20401999 - 2⁹ = 20401487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20401919) 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, 3504 + ... + 7285.

It is an arithmetic number, because the mean of its divisors is an integer number (2675920).

Almost surely, 2^20401999 is an apocalyptic number.

20401999 is a deficient number, since it is larger than the sum of its proper divisors (1005361).

20401999 is a wasteful number, since it uses less digits than its factorization.

20401999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10881.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 20401999 is about 4516.8572038531. The cubic root of 20401999 is about 273.2483662468.

The spelling of 20401999 in words is "twenty million, four hundred one thousand, nine hundred ninety-nine".