155689640 has 32 divisors (see below), whose sum is σ = 352080000. Its totient is φ = 61959744.

The previous prime is 155689637. The next prime is 155689649. The reversal of 155689640 is 46986551.

It is a junction number, because it is equal to n+sod(n) for n = 155689591 and 155689600.

It is not an unprimeable number, because it can be changed into a prime (155689649) 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, 1820 + ... + 17739.

It is an arithmetic number, because the mean of its divisors is an integer number (11002500).

Almost surely, 2^155689640 is an apocalyptic number.

155689640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155689640 is an abundant number, since it is smaller than the sum of its proper divisors (196390360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

155689640 is a wasteful number, since it uses less digits than its factorization.

155689640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19769 (or 19765 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 155689640 is about 12477.5654676704. The cubic root of 155689640 is about 537.9640297856.

The spelling of 155689640 in words is "one hundred fifty-five million, six hundred eighty-nine thousand, six hundred forty".