1554991 has 8 divisors (see below), whose sum is σ = 1624064. Its totient is φ = 1487160.

The previous prime is 1554989. The next prime is 1555013. The reversal of 1554991 is 1994551.

It is a happy number.

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

It is a 7-Lehmer number, since φ(1554991) divides (1554991-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 1554991 - 2¹ = 1554989 is a prime.

It is an Ulam number.

It is a Duffinian number.

1554991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1554391) 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, 2950 + ... + 3436.

It is an arithmetic number, because the mean of its divisors is an integer number (203008).

2^1554991 is an apocalyptic number.

1554991 is a deficient number, since it is larger than the sum of its proper divisors (69073).

1554991 is a wasteful number, since it uses less digits than its factorization.

1554991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621.

The product of its digits is 8100, while the sum is 34.

The square root of 1554991 is about 1246.9927826575. The cubic root of 1554991 is about 115.8535359181.

The spelling of 1554991 in words is "one million, five hundred fifty-four thousand, nine hundred ninety-one".