75220781 has 4 divisors (see below), whose sum is σ = 75410652. Its totient is φ = 75030912.

The previous prime is 75220777. The next prime is 75220853. The reversal of 75220781 is 18702257.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18702257 = 7 ⋅2671751.

It can be written as a sum of positive squares in 2 ways, for example, as 24098281 + 51122500 = 4909^2 + 7150^2 .

It is a cyclic number.

It is not a de Polignac number, because 75220781 - 2² = 75220777 is a prime.

It is a super-2 number, since 2×75220781² = 11316331788499922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75220721) 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, 94340 + ... + 95133.

It is an arithmetic number, because the mean of its divisors is an integer number (18852663).

Almost surely, 2^75220781 is an apocalyptic number.

It is an amenable number.

75220781 is a deficient number, since it is larger than the sum of its proper divisors (189871).

75220781 is a wasteful number, since it uses less digits than its factorization.

75220781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189870.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 75220781 is about 8672.9914677694. The cubic root of 75220781 is about 422.1297359472.

The spelling of 75220781 in words is "seventy-five million, two hundred twenty thousand, seven hundred eighty-one".