61721545 has 8 divisors (see below), whose sum is σ = 74223360. Its totient is φ = 49272240.

The previous prime is 61721533. The next prime is 61721549. The reversal of 61721545 is 54512716.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-61721545 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61721549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10491 + ... + 15280.

It is an arithmetic number, because the mean of its divisors is an integer number (9277920).

Almost surely, 2^61721545 is an apocalyptic number.

It is an amenable number.

61721545 is a deficient number, since it is larger than the sum of its proper divisors (12501815).

61721545 is a wasteful number, since it uses less digits than its factorization.

61721545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26255.

The product of its digits is 8400, while the sum is 31.

The square root of 61721545 is about 7856.3060658302. The cubic root of 61721545 is about 395.1957476616.

The spelling of 61721545 in words is "sixty-one million, seven hundred twenty-one thousand, five hundred forty-five".