61764721 has 4 divisors (see below), whose sum is σ = 63078912. Its totient is φ = 60450532.

The previous prime is 61764719. The next prime is 61764733. The reversal of 61764721 is 12746716.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61764721 - 2¹ = 61764719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61764701) 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, 657025 + ... + 657118.

It is an arithmetic number, because the mean of its divisors is an integer number (15769728).

Almost surely, 2^61764721 is an apocalyptic number.

It is an amenable number.

61764721 is a deficient number, since it is larger than the sum of its proper divisors (1314191).

61764721 is a wasteful number, since it uses less digits than its factorization.

61764721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1314190.

The product of its digits is 14112, while the sum is 34.

The square root of 61764721 is about 7859.0534417320. The cubic root of 61764721 is about 395.2878764553.

The spelling of 61764721 in words is "sixty-one million, seven hundred sixty-four thousand, seven hundred twenty-one".