61218737947 has 4 divisors (see below), whose sum is σ = 61351533936. Its totient is φ = 61085941960.

The previous prime is 61218737929. The next prime is 61218737953. The reversal of 61218737947 is 74973781216.

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

It is a cyclic number.

It is not a de Polignac number, because 61218737947 - 2¹⁹ = 61218213659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61218737917) 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, 66397303 + ... + 66398224.

It is an arithmetic number, because the mean of its divisors is an integer number (15337883484).

Almost surely, 2^61218737947 is an apocalyptic number.

61218737947 is a deficient number, since it is larger than the sum of its proper divisors (132795989).

61218737947 is a wasteful number, since it uses less digits than its factorization.

61218737947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132795988.

The product of its digits is 3556224, while the sum is 55.

The spelling of 61218737947 in words is "sixty-one billion, two hundred eighteen million, seven hundred thirty-seven thousand, nine hundred forty-seven".