1621457 has 2 divisors, whose sum is σ = 1621458. Its totient is φ = 1621456.

The previous prime is 1621439. The next prime is 1621469. The reversal of 1621457 is 7541261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1256641 + 364816 = 1121^2 + 604^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621457 - 2¹⁸ = 1359313 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810728 + 810729.

It is an arithmetic number, because the mean of its divisors is an integer number (810729).

2^1621457 is an apocalyptic number.

It is an amenable number.

1621457 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621457 is an equidigital number, since it uses as much as digits as its factorization.

1621457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 26.

The square root of 1621457 is about 1273.3644411558. The cubic root of 1621457 is about 117.4812283276.

The spelling of 1621457 in words is "one million, six hundred twenty-one thousand, four hundred fifty-seven".