77248721 has 16 divisors (see below), whose sum is σ = 87989760. Its totient is φ = 67173120.

The previous prime is 77248709. The next prime is 77248727. The reversal of 77248721 is 12784277.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 77248721 - 2¹⁸ = 76986577 is a prime.

It is a super-2 number, since 2×77248721² = 11934729792271682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77248727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34976 + ... + 37118.

It is an arithmetic number, because the mean of its divisors is an integer number (5499360).

Almost surely, 2^77248721 is an apocalyptic number.

It is an amenable number.

77248721 is a deficient number, since it is larger than the sum of its proper divisors (10741039).

77248721 is a wasteful number, since it uses less digits than its factorization.

77248721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2296.

The product of its digits is 43904, while the sum is 38.

The square root of 77248721 is about 8789.1251555544. The cubic root of 77248721 is about 425.8896629906.

The spelling of 77248721 in words is "seventy-seven million, two hundred forty-eight thousand, seven hundred twenty-one".