100621861 has 4 divisors (see below), whose sum is σ = 106540812. Its totient is φ = 94702912.

The previous prime is 100621819. The next prime is 100621903. The reversal of 100621861 is 168126001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168126001 = 43 ⋅3909907.

It is an interprime number because it is at equal distance from previous prime (100621819) and next prime (100621903).

It can be written as a sum of positive squares in 2 ways, for example, as 78588225 + 22033636 = 8865^2 + 4694^2 .

It is a cyclic number.

It is not a de Polignac number, because 100621861 - 2⁷ = 100621733 is a prime.

It is a super-2 number, since 2×100621861² = 20249517822206642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100621361) 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, 2959450 + ... + 2959483.

It is an arithmetic number, because the mean of its divisors is an integer number (26635203).

Almost surely, 2^100621861 is an apocalyptic number.

It is an amenable number.

100621861 is a deficient number, since it is larger than the sum of its proper divisors (5918951).

100621861 is an equidigital number, since it uses as much as digits as its factorization.

100621861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5918950.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 100621861 is about 10031.0448608308. The cubic root of 100621861 is about 465.1190368543.

Adding to 100621861 its reverse (168126001), we get a palindrome (268747862).

The spelling of 100621861 in words is "one hundred million, six hundred twenty-one thousand, eight hundred sixty-one".