661622101 has 8 divisors (see below), whose sum is σ = 756451904. Its totient is φ = 566870400.

The previous prime is 661622083. The next prime is 661622107. The reversal of 661622101 is 101226166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 11-Lehmer number, since φ(661622101) divides (661622101-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 661622101 - 2⁷ = 661621973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661622107) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75 + ... + 36376.

It is an arithmetic number, because the mean of its divisors is an integer number (94556488).

Almost surely, 2^661622101 is an apocalyptic number.

It is an amenable number.

661622101 is a deficient number, since it is larger than the sum of its proper divisors (94829803).

661622101 is a wasteful number, since it uses less digits than its factorization.

661622101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39051.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 661622101 is about 25722.0158813418. The cubic root of 661622101 is about 871.3714666039.

Adding to 661622101 its reverse (101226166), we get a palindrome (762848267).

The spelling of 661622101 in words is "six hundred sixty-one million, six hundred twenty-two thousand, one hundred one".