1615961 has 4 divisors (see below), whose sum is σ = 1619124. Its totient is φ = 1612800.

The previous prime is 1615949. The next prime is 1615963. The reversal of 1615961 is 1695161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 577600 + 1038361 = 760^2 + 1019^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1615961 is a prime.

It is a super-2 number, since 2×1615961² = 5222659907042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1615963) 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, 620 + ... + 1901.

It is an arithmetic number, because the mean of its divisors is an integer number (404781).

2^1615961 is an apocalyptic number.

1615961 is the 569-th centered decagonal number.

It is an amenable number.

1615961 is a deficient number, since it is larger than the sum of its proper divisors (3163).

1615961 is an equidigital number, since it uses as much as digits as its factorization.

1615961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3162.

The product of its digits is 1620, while the sum is 29.

The square root of 1615961 is about 1271.2045468767. The cubic root of 1615961 is about 117.3483421385.

The spelling of 1615961 in words is "one million, six hundred fifteen thousand, nine hundred sixty-one".