51017661 has 16 divisors (see below), whose sum is σ = 78021120. Its totient is φ = 32914080.

The previous prime is 51017639. The next prime is 51017677. The reversal of 51017661 is 16671015.

It is not a de Polignac number, because 51017661 - 2⁶ = 51017597 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51017861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29640 + ... + 31313.

It is an arithmetic number, because the mean of its divisors is an integer number (4876320).

Almost surely, 2^51017661 is an apocalyptic number.

It is an amenable number.

51017661 is a deficient number, since it is larger than the sum of its proper divisors (27003459).

51017661 is a wasteful number, since it uses less digits than its factorization.

51017661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60993 (or 60987 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 51017661 is about 7142.6648388399. The cubic root of 51017661 is about 370.8857789001.

Adding to 51017661 its reverse (16671015), we get a palindrome (67688676).

The spelling of 51017661 in words is "fifty-one million, seventeen thousand, six hundred sixty-one".