21157045 has 16 divisors (see below), whose sum is σ = 31248000. Its totient is φ = 13391424.

The previous prime is 21157043. The next prime is 21157049. The reversal of 21157045 is 54075112.

It is a cyclic number.

It is not a de Polignac number, because 21157045 - 2¹ = 21157043 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22795 + ... + 23704.

It is an arithmetic number, because the mean of its divisors is an integer number (1953000).

Almost surely, 2^21157045 is an apocalyptic number.

It is an amenable number.

21157045 is a deficient number, since it is larger than the sum of its proper divisors (10090955).

21157045 is a wasteful number, since it uses less digits than its factorization.

21157045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46524.

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 21157045 is about 4599.6787931333. The cubic root of 21157045 is about 276.5784488339.

The spelling of 21157045 in words is "twenty-one million, one hundred fifty-seven thousand, forty-five".