61011721 has 9 divisors (see below), whose sum is σ = 62442471. Its totient is φ = 59613552.

The previous prime is 61011697. The next prime is 61011733. The reversal of 61011721 is 12711016.

The square root of 61011721 is 7811.

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

It can be written as a sum of positive squares in only one way, i.e., 34633225 + 26378496 = 5885^2 + 5136^2 .

It is not a de Polignac number, because 61011721 - 2¹¹ = 61009673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61011221) 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, 570150 + ... + 570256.

Almost surely, 2^61011721 is an apocalyptic number.

61011721 is the 7811-st square number.

61011721 is the 3906-th centered octagonal number.

It is an amenable number.

61011721 is a deficient number, since it is larger than the sum of its proper divisors (1430750).

61011721 is an frugal number, since it uses more digits than its factorization.

61011721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 19.

The cubic root of 61011721 is about 393.6749296373.

Adding to 61011721 its reverse (12711016), we get a palindrome (73722737).

The spelling of 61011721 in words is "sixty-one million, eleven thousand, seven hundred twenty-one".