100725421 has 4 divisors (see below), whose sum is σ = 101165500. Its totient is φ = 100285344.

The previous prime is 100725419. The next prime is 100725437. The reversal of 100725421 is 124527001.

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: 124527001 = 8243 ⋅15107.

It can be written as a sum of positive squares in 2 ways, for example, as 58293225 + 42432196 = 7635^2 + 6514^2 .

It is a cyclic number.

It is not a de Polignac number, because 100725421 - 2¹ = 100725419 is a prime.

It is a super-4 number, since 4×100725421⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100725392 and 100725401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100725461) 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, 219696 + ... + 220153.

It is an arithmetic number, because the mean of its divisors is an integer number (25291375).

Almost surely, 2^100725421 is an apocalyptic number.

It is an amenable number.

100725421 is a deficient number, since it is larger than the sum of its proper divisors (440079).

100725421 is an equidigital number, since it uses as much as digits as its factorization.

100725421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440078.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 100725421 is about 10036.2055080593. The cubic root of 100725421 is about 465.2785489513.

The spelling of 100725421 in words is "one hundred million, seven hundred twenty-five thousand, four hundred twenty-one".