891864751 has 4 divisors (see below), whose sum is σ = 894908952. Its totient is φ = 888820552.

The previous prime is 891864749. The next prime is 891864781. The reversal of 891864751 is 157468198.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 157468198 = 2 ⋅78734099.

It is a cyclic number.

It is not a de Polignac number, because 891864751 - 2¹ = 891864749 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 891864695 and 891864704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891864781) 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, 1521661 + ... + 1522246.

It is an arithmetic number, because the mean of its divisors is an integer number (223727238).

Almost surely, 2^891864751 is an apocalyptic number.

891864751 is a deficient number, since it is larger than the sum of its proper divisors (3044201).

891864751 is a wasteful number, since it uses less digits than its factorization.

891864751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3044200.

The product of its digits is 483840, while the sum is 49.

The square root of 891864751 is about 29864.1047245686. The cubic root of 891864751 is about 962.5715023285.

The spelling of 891864751 in words is "eight hundred ninety-one million, eight hundred sixty-four thousand, seven hundred fifty-one".