61506981 has 12 divisors (see below), whose sum is σ = 89433760. Its totient is φ = 40732200.

The previous prime is 61506979. The next prime is 61506983. The reversal of 61506981 is 18960516.

61506981 is a `hidden beast` number, since 61 + 506 + 98 + 1 = 666.

61506981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (61506979) and next prime (61506983).

It is not a de Polignac number, because 61506981 - 2¹ = 61506979 is a prime.

It is a super-2 number, since 2×61506981² = 7566217423468722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61506983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21271 + ... + 23988.

Almost surely, 2^61506981 is an apocalyptic number.

It is an amenable number.

61506981 is a deficient number, since it is larger than the sum of its proper divisors (27926779).

61506981 is a wasteful number, since it uses less digits than its factorization.

61506981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45416 (or 45413 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 61506981 is about 7842.6386503523. The cubic root of 61506981 is about 394.7372733497.

It can be divided in two parts, 6150 and 6981, that added together give a palindrome (13131).

The spelling of 61506981 in words is "sixty-one million, five hundred six thousand, nine hundred eighty-one".