61530021 has 48 divisors (see below), whose sum is σ = 109160064. Its totient is φ = 32596992.

The previous prime is 61530011. The next prime is 61530041. The reversal of 61530021 is 12003516.

61530021 is a `hidden beast` number, since 615 + 30 + 0 + 21 = 666.

It is not a de Polignac number, because 61530021 - 2⁶ = 61529957 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 61529976 and 61530003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61530011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77790 + ... + 78576.

It is an arithmetic number, because the mean of its divisors is an integer number (2274168).

Almost surely, 2^61530021 is an apocalyptic number.

It is an amenable number.

61530021 is a deficient number, since it is larger than the sum of its proper divisors (47630043).

61530021 is a wasteful number, since it uses less digits than its factorization.

61530021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890 (or 887 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 61530021 is about 7844.1074061999. The cubic root of 61530021 is about 394.7865556223.

Adding to 61530021 its reverse (12003516), we get a palindrome (73533537).

The spelling of 61530021 in words is "sixty-one million, five hundred thirty thousand, twenty-one".