1554551491 has 4 divisors (see below), whose sum is σ = 1554989184. Its totient is φ = 1554113800.

The previous prime is 1554551489. The next prime is 1554551521. The reversal of 1554551491 is 1941554551.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1554551491 - 2¹ = 1554551489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1554551431) 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, 213475 + ... + 220636.

It is an arithmetic number, because the mean of its divisors is an integer number (388747296).

Almost surely, 2^1554551491 is an apocalyptic number.

1554551491 is a deficient number, since it is larger than the sum of its proper divisors (437693).

1554551491 is an equidigital number, since it uses as much as digits as its factorization.

1554551491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437692.

The product of its digits is 90000, while the sum is 40.

The square root of 1554551491 is about 39427.8009911788. The cubic root of 1554551491 is about 1158.4261978421.

The spelling of 1554551491 in words is "one billion, five hundred fifty-four million, five hundred fifty-one thousand, four hundred ninety-one".