30761821 has 2 divisors, whose sum is σ = 30761822. Its totient is φ = 30761820.

The previous prime is 30761791. The next prime is 30761867. The reversal of 30761821 is 12816703.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30525625 + 236196 = 5525^2 + 486^2 .

It is an emirp because it is prime and its reverse (12816703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30761821 - 2⁹ = 30761309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 30761821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30764821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15380910 + 15380911.

It is an arithmetic number, because the mean of its divisors is an integer number (15380911).

Almost surely, 2^30761821 is an apocalyptic number.

It is an amenable number.

30761821 is a deficient number, since it is larger than the sum of its proper divisors (1).

30761821 is an equidigital number, since it uses as much as digits as its factorization.

30761821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 30761821 is about 5546.3340144640. The cubic root of 30761821 is about 313.3314680992.

It can be divided in two parts, 307 and 61821, that added together give a triangular number (62128 = T₃₅₂).

The spelling of 30761821 in words is "thirty million, seven hundred sixty-one thousand, eight hundred twenty-one".