661377 has 8 divisors (see below), whose sum is σ = 885600. Its totient is φ = 439040.

The previous prime is 661373. The next prime is 661393. The reversal of 661377 is 773166.

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

It is a cyclic number.

It is not a de Polignac number, because 661377 - 2² = 661373 is a prime.

It is a super-2 number, since 2×661377² = 874839072258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661373) 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, 1102 + ... + 1592.

It is an arithmetic number, because the mean of its divisors is an integer number (110700).

2⁶⁶¹³⁷⁷ is an apocalyptic number.

It is an amenable number.

661377 is a deficient number, since it is larger than the sum of its proper divisors (224223).

661377 is a wasteful number, since it uses less digits than its factorization.

661377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 943.

The product of its digits is 5292, while the sum is 30.

The square root of 661377 is about 813.2508837991. The cubic root of 661377 is about 87.1263852103.

Subtracting from 661377 its product of digits (5292), we obtain a triangular number (656085 = T₁₁₄₅).

The spelling of 661377 in words is "six hundred sixty-one thousand, three hundred seventy-seven".