61651537 has 4 divisors (see below), whose sum is σ = 65278116. Its totient is φ = 58024960.

The previous prime is 61651531. The next prime is 61651543. The reversal of 61651537 is 73515616.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (61651531) and next prime (61651543).

It can be written as a sum of positive squares in 2 ways, for example, as 45643536 + 16008001 = 6756^2 + 4001^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61651537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61651531) 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, 1813264 + ... + 1813297.

It is an arithmetic number, because the mean of its divisors is an integer number (16319529).

Almost surely, 2^61651537 is an apocalyptic number.

It is an amenable number.

61651537 is a deficient number, since it is larger than the sum of its proper divisors (3626579).

61651537 is a wasteful number, since it uses less digits than its factorization.

61651537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3626578.

The product of its digits is 18900, while the sum is 34.

The square root of 61651537 is about 7851.8492726236. The cubic root of 61651537 is about 395.0462734872.

The spelling of 61651537 in words is "sixty-one million, six hundred fifty-one thousand, five hundred thirty-seven".