100561021 has 4 divisors (see below), whose sum is σ = 109702944. Its totient is φ = 91419100.

The previous prime is 100561007. The next prime is 100561031. The reversal of 100561021 is 120165001.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120165001 = 11 ⋅10924091.

It is a cyclic number.

It is not a de Polignac number, because 100561021 - 2⁵ = 100560989 is a prime.

It is a super-2 number, since 2×100561021² = 20225037889124882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100560986 and 100561004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100561031) 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, 4570945 + ... + 4570966.

It is an arithmetic number, because the mean of its divisors is an integer number (27425736).

Almost surely, 2^100561021 is an apocalyptic number.

100561021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

100561021 is a deficient number, since it is larger than the sum of its proper divisors (9141923).

100561021 is an equidigital number, since it uses as much as digits as its factorization.

100561021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9141922.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 100561021 is about 10028.0118169057. The cubic root of 100561021 is about 465.0252747660.

It can be divided in two parts, 1005 and 61021, that added together give a palindrome (62026).

The spelling of 100561021 in words is "one hundred million, five hundred sixty-one thousand, twenty-one".