61817661 has 20 divisors (see below), whose sum is σ = 97779132. Its totient is φ = 38786688.

The previous prime is 61817611. The next prime is 61817669. The reversal of 61817661 is 16671816.

It can be written as a sum of positive squares in 2 ways, for example, as 40832100 + 20985561 = 6390^2 + 4581^2 .

It is not a de Polignac number, because 61817661 - 2⁹ = 61817149 is a prime.

It is a super-3 number, since 3×61817661³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61817669) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 21070 + ... + 23823.

Almost surely, 2^61817661 is an apocalyptic number.

It is an amenable number.

61817661 is a deficient number, since it is larger than the sum of its proper divisors (35961471).

61817661 is a wasteful number, since it uses less digits than its factorization.

61817661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44922 (or 44913 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 61817661 is about 7862.4208104120. The cubic root of 61817661 is about 395.4007810596.

The spelling of 61817661 in words is "sixty-one million, eight hundred seventeen thousand, six hundred sixty-one".