102661721 has 4 divisors (see below), whose sum is σ = 102996432. Its totient is φ = 102327012.

The previous prime is 102661703. The next prime is 102661751. The reversal of 102661721 is 127166201.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102661721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (102661751) 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, 166895 + ... + 167508.

It is an arithmetic number, because the mean of its divisors is an integer number (25749108).

Almost surely, 2^102661721 is an apocalyptic number.

It is an amenable number.

102661721 is a deficient number, since it is larger than the sum of its proper divisors (334711).

102661721 is an equidigital number, since it uses as much as digits as its factorization.

102661721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334710.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 102661721 is about 10132.2120487088. The cubic root of 102661721 is about 468.2410807121.

The spelling of 102661721 in words is "one hundred two million, six hundred sixty-one thousand, seven hundred twenty-one".