661749299 has 4 divisors (see below), whose sum is σ = 661905336. Its totient is φ = 661593264.

The previous prime is 661749287. The next prime is 661749301. The reversal of 661749299 is 992947166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 992947166 = 2 ⋅496473583.

It is a cyclic number.

It is not a de Polignac number, because 661749299 - 2²⁰ = 660700723 is a prime.

It is a super-3 number, since 3×661749299³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661749299.

It is not an unprimeable number, because it can be changed into a prime (661749239) 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, 71474 + ... + 80199.

It is an arithmetic number, because the mean of its divisors is an integer number (165476334).

Almost surely, 2^661749299 is an apocalyptic number.

661749299 is a deficient number, since it is larger than the sum of its proper divisors (156037).

661749299 is a wasteful number, since it uses less digits than its factorization.

661749299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156036.

The product of its digits is 1469664, while the sum is 53.

The square root of 661749299 is about 25724.4883136672. The cubic root of 661749299 is about 871.4273039193.

The spelling of 661749299 in words is "six hundred sixty-one million, seven hundred forty-nine thousand, two hundred ninety-nine".