1655540491 has 4 divisors (see below), whose sum is σ = 1806044184. Its totient is φ = 1505036800.

The previous prime is 1655540479. The next prime is 1655540503. The reversal of 1655540491 is 1940455561.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (1655540479) and next prime (1655540503).

It is a cyclic number.

It is not a de Polignac number, because 1655540491 - 2⁷ = 1655540363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1655540401) 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, 75251830 + ... + 75251851.

It is an arithmetic number, because the mean of its divisors is an integer number (451511046).

Almost surely, 2^1655540491 is an apocalyptic number.

1655540491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1655540491 is a deficient number, since it is larger than the sum of its proper divisors (150503693).

1655540491 is a wasteful number, since it uses less digits than its factorization.

1655540491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150503692.

The product of its (nonzero) digits is 108000, while the sum is 40.

The square root of 1655540491 is about 40688.3335982195. Note that the first 3 decimals coincide. The cubic root of 1655540491 is about 1182.9869007881.

The spelling of 1655540491 in words is "one billion, six hundred fifty-five million, five hundred forty thousand, four hundred ninety-one".