921140781 has 8 divisors (see below), whose sum is σ = 1339841184. Its totient is φ = 558267120.

The previous prime is 921140707. The next prime is 921140813. The reversal of 921140781 is 187041129.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 921140781 - 2¹⁴ = 921124397 is a prime.

It is a super-2 number, since 2×921140781² = 1697000676842579922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 27913357 = 921140781 / (9 + 2 + 1 + 1 + 4 + 0 + 7 + 8 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921144781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13956646 + ... + 13956711.

It is an arithmetic number, because the mean of its divisors is an integer number (167480148).

Almost surely, 2^921140781 is an apocalyptic number.

It is an amenable number.

921140781 is a deficient number, since it is larger than the sum of its proper divisors (418700403).

921140781 is a wasteful number, since it uses less digits than its factorization.

921140781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27913371.

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 921140781 is about 30350.3011681927. The cubic root of 921140781 is about 972.9906568635.

The spelling of 921140781 in words is "nine hundred twenty-one million, one hundred forty thousand, seven hundred eighty-one".