890723921 has 4 divisors (see below), whose sum is σ = 929451072. Its totient is φ = 851996772.

The previous prime is 890723861. The next prime is 890723963. The reversal of 890723921 is 129327098.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129327098 = 2 ⋅64663549.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-890723921 is a prime.

It is a super-2 number, since 2×890723921² = 1586778206883228482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (890723521) 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, 19363541 + ... + 19363586.

It is an arithmetic number, because the mean of its divisors is an integer number (232362768).

Almost surely, 2^890723921 is an apocalyptic number.

It is an amenable number.

890723921 is a deficient number, since it is larger than the sum of its proper divisors (38727151).

890723921 is a wasteful number, since it uses less digits than its factorization.

890723921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38727150.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 890723921 is about 29844.9982576645. The cubic root of 890723921 is about 962.1609023267.

The spelling of 890723921 in words is "eight hundred ninety million, seven hundred twenty-three thousand, nine hundred twenty-one".