772561921 has 4 divisors (see below), whose sum is σ = 773433792. Its totient is φ = 771690052.

The previous prime is 772561913. The next prime is 772561931. The reversal of 772561921 is 129165277.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129165277 = 4327 ⋅29851.

It is a cyclic number.

It is not a de Polignac number, because 772561921 - 2³ = 772561913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (772561901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 434605 + ... + 436378.

It is an arithmetic number, because the mean of its divisors is an integer number (193358448).

Almost surely, 2^772561921 is an apocalyptic number.

It is an amenable number.

772561921 is a deficient number, since it is larger than the sum of its proper divisors (871871).

772561921 is an equidigital number, since it uses as much as digits as its factorization.

772561921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871870.

The product of its digits is 52920, while the sum is 40.

The square root of 772561921 is about 27794.9981291599. The cubic root of 772561921 is about 917.5810434095.

The spelling of 772561921 in words is "seven hundred seventy-two million, five hundred sixty-one thousand, nine hundred twenty-one".