100142721 has 18 divisors (see below), whose sum is σ = 168267762. Its totient is φ = 57224160.

The previous prime is 100142717. The next prime is 100142723. The reversal of 100142721 is 127241001.

It can be written as a sum of positive squares in only one way, i.e., 70560000 + 29582721 = 8400^2 + 5439^2 .

It is not a de Polignac number, because 100142721 - 2² = 100142717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 100142694 and 100142703.

It is not an unprimeable number, because it can be changed into a prime (100142723) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 113100 + ... + 113981.

It is an arithmetic number, because the mean of its divisors is an integer number (9348209).

Almost surely, 2^100142721 is an apocalyptic number.

It is an amenable number.

100142721 is a deficient number, since it is larger than the sum of its proper divisors (68125041).

100142721 is a wasteful number, since it uses less digits than its factorization.

100142721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227101 (or 227091 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 100142721 is about 10007.1335056549. The cubic root of 100142721 is about 464.3795957935.

Adding to 100142721 its reverse (127241001), we get a palindrome (227383722).

The spelling of 100142721 in words is "one hundred million, one hundred forty-two thousand, seven hundred twenty-one".