20100321 has 12 divisors (see below), whose sum is σ = 30296448. Its totient is φ = 12817464.

The previous prime is 20100317. The next prime is 20100329. The reversal of 20100321 is 12300102.

It is a happy number.

It is not a de Polignac number, because 20100321 - 2² = 20100317 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (20100329) 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, 48345 + ... + 48758.

It is an arithmetic number, because the mean of its divisors is an integer number (2524704).

Almost surely, 2^20100321 is an apocalyptic number.

It is an amenable number.

20100321 is a deficient number, since it is larger than the sum of its proper divisors (10196127).

20100321 is a wasteful number, since it uses less digits than its factorization.

20100321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97132 (or 97129 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 20100321 is about 4483.3381536529. The cubic root of 20100321 is about 271.8948600633.

Adding to 20100321 its reverse (12300102), we get a palindrome (32400423).

The spelling of 20100321 in words is "twenty million, one hundred thousand, three hundred twenty-one".