155209905 has 32 divisors (see below), whose sum is σ = 279832320. Its totient is φ = 81607680.

The previous prime is 155209883. The next prime is 155209927. The reversal of 155209905 is 509902551.

It is an interprime number because it is at equal distance from previous prime (155209883) and next prime (155209927).

It is not a de Polignac number, because 155209905 - 2¹⁸ = 154947761 is a prime.

It is a super-2 number, since 2×155209905² = 48180229220218050, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 155209905.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1489 + ... + 17681.

It is an arithmetic number, because the mean of its divisors is an integer number (8744760).

Almost surely, 2^155209905 is an apocalyptic number.

155209905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

155209905 is a deficient number, since it is larger than the sum of its proper divisors (124622415).

155209905 is a wasteful number, since it uses less digits than its factorization.

155209905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16278 (or 16272 counting only the distinct ones).

The product of its (nonzero) digits is 20250, while the sum is 36.

The square root of 155209905 is about 12458.3267335546. The cubic root of 155209905 is about 537.4109086158.

It can be divided in two parts, 15520 and 9905, that added together give a triangular number (25425 = T₂₂₅).

The spelling of 155209905 in words is "one hundred fifty-five million, two hundred nine thousand, nine hundred five".