621542 has 4 divisors (see below), whose sum is σ = 932316. Its totient is φ = 310770.

The previous prime is 621541. The next prime is 621583. The reversal of 621542 is 245126.

It is a happy number.

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

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155384 + ... + 155387.

It is an arithmetic number, because the mean of its divisors is an integer number (233079).

2⁶²¹⁵⁴² is an apocalyptic number.

621542 is a deficient number, since it is larger than the sum of its proper divisors (310774).

621542 is a wasteful number, since it uses less digits than its factorization.

621542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310773.

The product of its digits is 480, while the sum is 20.

The square root of 621542 is about 788.3793503130. The cubic root of 621542 is about 85.3408230460.

Adding to 621542 its reverse (245126), we get a palindrome (866668).

The spelling of 621542 in words is "six hundred twenty-one thousand, five hundred forty-two".