155921407 has 2 divisors, whose sum is σ = 155921408. Its totient is φ = 155921406.

The previous prime is 155921383. The next prime is 155921417. The reversal of 155921407 is 704129551.

It is a strong prime.

It is an emirp because it is prime and its reverse (704129551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155921407 - 2⁷ = 155921279 is a prime.

It is a super-2 number, since 2×155921407² = 48622970321719298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155921417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77960703 + 77960704.

It is an arithmetic number, because the mean of its divisors is an integer number (77960704).

Almost surely, 2^155921407 is an apocalyptic number.

155921407 is a deficient number, since it is larger than the sum of its proper divisors (1).

155921407 is an equidigital number, since it uses as much as digits as its factorization.

155921407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 34.

The square root of 155921407 is about 12486.8493624293. The cubic root of 155921407 is about 538.2308437090.

The spelling of 155921407 in words is "one hundred fifty-five million, nine hundred twenty-one thousand, four hundred seven".