155401581 has 4 divisors (see below), whose sum is σ = 207202112. Its totient is φ = 103601052.

The previous prime is 155401579. The next prime is 155401621. The reversal of 155401581 is 185104551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 155401581 - 2¹ = 155401579 is a prime.

It is a super-2 number, since 2×155401581² = 48299302754599122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155401511) 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, 25900261 + ... + 25900266.

It is an arithmetic number, because the mean of its divisors is an integer number (51800528).

Almost surely, 2^155401581 is an apocalyptic number.

It is an amenable number.

155401581 is a deficient number, since it is larger than the sum of its proper divisors (51800531).

155401581 is an equidigital number, since it uses as much as digits as its factorization.

155401581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51800530.

The product of its (nonzero) digits is 4000, while the sum is 30.

The square root of 155401581 is about 12466.0170463545. The cubic root of 155401581 is about 537.6320422669.

The spelling of 155401581 in words is "one hundred fifty-five million, four hundred one thousand, five hundred eighty-one".