155697421 has 8 divisors (see below), whose sum is σ = 169952544. Its totient is φ = 141459120.

The previous prime is 155697413. The next prime is 155697431. The reversal of 155697421 is 124796551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 155697421 - 2³ = 155697413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155697431) 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, 22630 + ... + 28696.

It is an arithmetic number, because the mean of its divisors is an integer number (21244068).

Almost surely, 2^155697421 is an apocalyptic number.

155697421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155697421 is a deficient number, since it is larger than the sum of its proper divisors (14255123).

155697421 is a wasteful number, since it uses less digits than its factorization.

155697421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8411.

The product of its digits is 75600, while the sum is 40.

The square root of 155697421 is about 12477.8772633810. The cubic root of 155697421 is about 537.9729916929.

The spelling of 155697421 in words is "one hundred fifty-five million, six hundred ninety-seven thousand, four hundred twenty-one".