30781826921 has 4 divisors (see below), whose sum is σ = 30898868352. Its totient is φ = 30664785492.

The previous prime is 30781826909. The next prime is 30781826987. The reversal of 30781826921 is 12962818703.

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 30781826921 - 2⁶ = 30781826857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30781826021) 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, 58520321 + ... + 58520846.

It is an arithmetic number, because the mean of its divisors is an integer number (7724717088).

Almost surely, 2^30781826921 is an apocalyptic number.

It is an amenable number.

30781826921 is a deficient number, since it is larger than the sum of its proper divisors (117041431).

30781826921 is a wasteful number, since it uses less digits than its factorization.

30781826921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117041430.

The product of its (nonzero) digits is 290304, while the sum is 47.

The spelling of 30781826921 in words is "thirty billion, seven hundred eighty-one million, eight hundred twenty-six thousand, nine hundred twenty-one".