15420121 has 8 divisors (see below), whose sum is σ = 15663560. Its totient is φ = 15178752.

The previous prime is 15420107. The next prime is 15420131. The reversal of 15420121 is 12102451.

It can be written as a sum of positive squares in 4 ways, for example, as 6056521 + 9363600 = 2461^2 + 3060^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15420121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15420095 and 15420104.

It is not an unprimeable number, because it can be changed into a prime (15420131) 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, 20671 + ... + 21403.

It is an arithmetic number, because the mean of its divisors is an integer number (1957945).

Almost surely, 2^15420121 is an apocalyptic number.

It is an amenable number.

15420121 is a deficient number, since it is larger than the sum of its proper divisors (243439).

15420121 is a wasteful number, since it uses less digits than its factorization.

15420121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 15420121 is about 3926.8461900105. The cubic root of 15420121 is about 248.9025010344.

Adding to 15420121 its reverse (12102451), we get a palindrome (27522572).

The spelling of 15420121 in words is "fifteen million, four hundred twenty thousand, one hundred twenty-one".