157821451 has 4 divisors (see below), whose sum is σ = 163263600. Its totient is φ = 152379304.

The previous prime is 157821431. The next prime is 157821463. The reversal of 157821451 is 154128751.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 154128751 = 7 ⋅22018393.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157821451 is a prime.

It is a super-2 number, since 2×157821451² = 49815220791490802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (157821431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2721031 + ... + 2721088.

It is an arithmetic number, because the mean of its divisors is an integer number (40815900).

Almost surely, 2^157821451 is an apocalyptic number.

157821451 is a deficient number, since it is larger than the sum of its proper divisors (5442149).

157821451 is an equidigital number, since it uses as much as digits as its factorization.

157821451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5442148.

The product of its digits is 11200, while the sum is 34.

The square root of 157821451 is about 12562.7007844651. The cubic root of 157821451 is about 540.4083000269.

The spelling of 157821451 in words is "one hundred fifty-seven million, eight hundred twenty-one thousand, four hundred fifty-one".