100021577 has 4 divisors (see below), whose sum is σ = 100049796. Its totient is φ = 99993360.

The previous prime is 100021487. The next prime is 100021583. The reversal of 100021577 is 775120001.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 775120001 = 31 ⋅25003871.

It can be written as a sum of positive squares in 2 ways, for example, as 80802121 + 19219456 = 8989^2 + 4384^2 .

It is a cyclic number.

It is not a de Polignac number, because 100021577 - 2¹⁴ = 100005193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100021177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7874 + ... + 16187.

It is an arithmetic number, because the mean of its divisors is an integer number (25012449).

Almost surely, 2^100021577 is an apocalyptic number.

It is an amenable number.

100021577 is a deficient number, since it is larger than the sum of its proper divisors (28219).

100021577 is an equidigital number, since it uses as much as digits as its factorization.

100021577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28218.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 100021577 is about 10001.0787918104. The cubic root of 100021577 is about 464.1922648146.

Adding to 100021577 its reverse (775120001), we get a palindrome (875141578).

The spelling of 100021577 in words is "one hundred million, twenty-one thousand, five hundred seventy-seven".