155639540 has 24 divisors (see below), whose sum is σ = 373535232. Its totient is φ = 53362080.

The previous prime is 155639537. The next prime is 155639543. The reversal of 155639540 is 45936551.

It is an interprime number because it is at equal distance from previous prime (155639537) and next prime (155639543).

It is a super-2 number, since 2×155639540² = 48447332822823200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 155639494 and 155639503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155639543) 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, 555716 + ... + 555995.

It is an arithmetic number, because the mean of its divisors is an integer number (15563968).

Almost surely, 2^155639540 is an apocalyptic number.

155639540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155639540 is an abundant number, since it is smaller than the sum of its proper divisors (217895692).

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

155639540 is a wasteful number, since it uses less digits than its factorization.

155639540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111727 (or 1111725 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 38.

The square root of 155639540 is about 12475.5577029646. The cubic root of 155639540 is about 537.9063190533.

The spelling of 155639540 in words is "one hundred fifty-five million, six hundred thirty-nine thousand, five hundred forty".