61639447 has 4 divisors (see below), whose sum is σ = 63305416. Its totient is φ = 59973480.

The previous prime is 61639429. The next prime is 61639453. The reversal of 61639447 is 74493616.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61639447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61639547) 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, 832929 + ... + 833002.

It is an arithmetic number, because the mean of its divisors is an integer number (15826354).

Almost surely, 2^61639447 is an apocalyptic number.

61639447 is a deficient number, since it is larger than the sum of its proper divisors (1665969).

61639447 is a wasteful number, since it uses less digits than its factorization.

61639447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1665968.

The product of its digits is 108864, while the sum is 40.

The square root of 61639447 is about 7851.0793525476. The cubic root of 61639447 is about 395.0204486556.

The spelling of 61639447 in words is "sixty-one million, six hundred thirty-nine thousand, four hundred forty-seven".