61548151921 has 3 divisors (see below), whose sum is σ = 61548400011. Its totient is φ = 61547903832.

The previous prime is 61548151901. The next prime is 61548151927. The reversal of 61548151921 is 12915184516.

The square root of 61548151921 is 248089.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 45245969521 + 16302182400 = 212711^2 + 127680^2 .

It is not a de Polignac number, because 61548151921 - 2¹³ = 61548143729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61548151927) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 124045 + ... + 372133.

It is an arithmetic number, because the mean of its divisors is an integer number (20516133337).

Almost surely, 2^61548151921 is an apocalyptic number.

61548151921 is the 248089-th square number.

61548151921 is the 124045-th centered octagonal number.

It is an amenable number.

61548151921 is a deficient number, since it is larger than the sum of its proper divisors (248090).

61548151921 is an frugal number, since it uses more digits than its factorization.

61548151921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496178 (or 248089 counting only the distinct ones).

The product of its digits is 86400, while the sum is 43.

The spelling of 61548151921 in words is "sixty-one billion, five hundred forty-eight million, one hundred fifty-one thousand, nine hundred twenty-one".