921000551 has 4 divisors (see below), whose sum is σ = 975177072. Its totient is φ = 866824032.

The previous prime is 921000541. The next prime is 921000593. The reversal of 921000551 is 155000129.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155000129 = 191 ⋅811519.

It is a cyclic number.

It is not a de Polignac number, because 921000551 - 2¹⁴ = 920984167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921000541) 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, 27088235 + ... + 27088268.

It is an arithmetic number, because the mean of its divisors is an integer number (243794268).

Almost surely, 2^921000551 is an apocalyptic number.

921000551 is a deficient number, since it is larger than the sum of its proper divisors (54176521).

921000551 is a wasteful number, since it uses less digits than its factorization.

921000551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54176520.

The product of its (nonzero) digits is 450, while the sum is 23.

The square root of 921000551 is about 30347.9908890193. The cubic root of 921000551 is about 972.9412799000.

The spelling of 921000551 in words is "nine hundred twenty-one million, five hundred fifty-one", and thus it is an aban number.