61538228761 has 9 divisors (see below), whose sum is σ = 61799556693. Its totient is φ = 61278004380.

The previous prime is 61538228737. The next prime is 61538228771. The reversal of 61538228761 is 16782283516.

It is a happy number.

The square root of 61538228761 is 248069.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 61538228761 - 2⁵ = 61538228729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61538228711) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 89056426 + ... + 89057116.

Almost surely, 2^61538228761 is an apocalyptic number.

61538228761 is the 248069-th square number.

61538228761 is the 124035-th centered octagonal number.

It is an amenable number.

61538228761 is a deficient number, since it is larger than the sum of its proper divisors (261327932).

61538228761 is an frugal number, since it uses more digits than its factorization.

61538228761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2100 (or 1050 counting only the distinct ones).

The product of its digits is 967680, while the sum is 49.

Multiplying 61538228761 by its sum of digits (49), we get a square (3015373209289 = 1736483²).

The spelling of 61538228761 in words is "sixty-one billion, five hundred thirty-eight million, two hundred twenty-eight thousand, seven hundred sixty-one".