155651661 has 12 divisors (see below), whose sum is σ = 245269440. Its totient is φ = 94334280.

The previous prime is 155651633. The next prime is 155651693. The reversal of 155651661 is 166156551.

It is not a de Polignac number, because 155651661 - 2⁶ = 155651597 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155651161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 786021 + ... + 786218.

It is an arithmetic number, because the mean of its divisors is an integer number (20439120).

Almost surely, 2^155651661 is an apocalyptic number.

155651661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155651661 is a deficient number, since it is larger than the sum of its proper divisors (89617779).

155651661 is a wasteful number, since it uses less digits than its factorization.

155651661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572256 (or 1572253 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

The square root of 155651661 is about 12476.0434834125. The cubic root of 155651661 is about 537.9202824999.

The spelling of 155651661 in words is "one hundred fifty-five million, six hundred fifty-one thousand, six hundred sixty-one".