106621781 has 4 divisors (see below), whose sum is σ = 121853472. Its totient is φ = 91390092.

The previous prime is 106621763. The next prime is 106621799. The reversal of 106621781 is 187126601.

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.

It is an interprime number because it is at equal distance from previous prime (106621763) and next prime (106621799).

It is a cyclic number.

It is not a de Polignac number, because 106621781 - 2¹⁰ = 106620757 is a prime.

It is a super-2 number, since 2×106621781² = 22736408367223922, 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 (106621751) 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, 7615835 + ... + 7615848.

It is an arithmetic number, because the mean of its divisors is an integer number (30463368).

Almost surely, 2^106621781 is an apocalyptic number.

It is an amenable number.

106621781 is a deficient number, since it is larger than the sum of its proper divisors (15231691).

106621781 is an equidigital number, since it uses as much as digits as its factorization.

106621781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15231690.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 106621781 is about 10325.7823432416. The cubic root of 106621781 is about 474.1859089625.

The spelling of 106621781 in words is "one hundred six million, six hundred twenty-one thousand, seven hundred eighty-one".