20402001 has 12 divisors (see below), whose sum is σ = 29511300. Its totient is φ = 13582080.

The previous prime is 20401973. The next prime is 20402009. The reversal of 20402001 is 10020402.

It can be written as a sum of positive squares in 2 ways, for example, as 15992001 + 4410000 = 3999^2 + 2100^2 .

It is not a de Polignac number, because 20402001 - 2⁹ = 20401489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20402009) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8361 + ... + 10521.

It is an arithmetic number, because the mean of its divisors is an integer number (2459275).

Almost surely, 2^20402001 is an apocalyptic number.

It is an amenable number.

20402001 is a deficient number, since it is larger than the sum of its proper divisors (9109299).

20402001 is a wasteful number, since it uses less digits than its factorization.

20402001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3216 (or 3213 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 20402001 is about 4516.8574252460. The cubic root of 20402001 is about 273.2483751756.

Adding to 20402001 its reverse (10020402), we get a palindrome (30422403).

The spelling of 20402001 in words is "twenty million, four hundred two thousand, one".